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The environmental risk of Lyme disease, defined by the density of Ixodes scapularis ticks and their prevalence of Borrelia burgdorferi infection, is increasing across the Ottawa, Ontario region, making this a unique location to explore the factors associated with environmental risk along a residential-woodland gradient. In this study, we collected I. scapularis ticks and trapped Peromyscus spp. mice, tested both for tick-borne pathogens, and monitored the intensity of foraging activity by deer in residential, woodland, and residential-woodland interface zones of four neighbourhoods. We constructed mixed-effect models to test for site-specific characteristics associated with densities of questing nymphal and adult ticks and the infection prevalence of nymphal and adult ticks. Compared to residential zones, we found a strong increasing gradient in tick density from interface to woodland zones, with 4 and 15 times as many nymphal ticks, respectively. Infection prevalence of nymphs and adults together was 15 to 24 times greater in non-residential zone habitats. Ecological site characteristics, including soil moisture, leaf litter depth, and understory density, were associated with variations in nymphal density and their infection prevalence. Our results suggest that high environmental risk bordering residential areas poses a concern for human-tick encounters, highlighting the need for targeted disease prevention., (© 2024. The Author(s).)

Importance: Respiratory syncytial virus (RSV) transmission was disrupted worldwide following the COVID-19 pandemic, and further study is required to better understand these changes., Objective: To compare observed and expected RSV hospital and intensive care unit (ICU) admission rates and characteristics of admitted children during the 2021-2022 and 2022-2023 seasons., Design, Setting, and Participants: A population-based cohort study of all children aged younger than 5 years in Ontario, Canada, July 1, 2017, through March 31, 2023, was conducted., Exposures: Individual and neighborhood-level sociodemographic and clinical characteristics were identified from administrative data, including age, palivizumab eligibility, complex medical conditions, rurality, and living in a marginalized neighborhood., Main Outcomes and Measures: The main outcome was RSV-associated hospitalization. Secondary outcomes included ICU admissions, mechanical ventilation, extracorporeal membrane oxygenation, and in-hospital death. Poisson generalized estimating equations were used to model weekly age- and sex-specific hospitalization rates and estimate expected rates in the postpandemic era; adjusted rate ratios (RRs) and 95% CIs are reported., Results: This cohort study included approximately 700 000 children per study year. Compared with prepandemic years (2017-2018, 2018-2019, and 2019-2020), the 2021-2022 RSV season peaked slightly earlier, but overall admission rates were comparable (289.1 vs 281.4-334.6 per 100 000, or approximately 2000 admissions). The 2022-2023 season peaked a month earlier and resulted in more than twice as many hospitalizations (770.0 per 100 000; n = 4977 admissions). The proportion of children admitted to an ICU in 2022-2023 (13.9%) was slightly higher than prepandemic (9.6%-11.4%); however, the population-based rate was triple the prepandemic levels (106.9 vs 27.6-36.6 per 100 000 children in Ontario). With the exception of palivizumab-eligible children, all sociodemographic and health status characteristics were associated with lower-than-expected RSV hospitalization rates in 2021-2022. In contrast, older age of patients was associated with higher-than-expected rates in 2022-2023 (ie, 24-59 months: RR, 1.90; 95% CI, 1.35-2.66)., Conclusions and Relevance: There were notable differences in RSV epidemiologic characteristics in Ontario following the COVID-19 pandemic. It is not yet clear whether and how long atypical RSV epidemics may persist. Clinicians and program planners should consider the potential for ongoing impacts to health care capacity and RSV immunization programs.

Aims: Rat-associated zoonotic pathogen transmission at the human-wildlife interface is a public health concern in urban environments where Norway rats (Rattus norvegicus) thrive on abundant anthropogenic resources and live in close contact with humans and other animal species. To identify potential factors influencing zoonotic pathogen occurrence in rats, we investigated associations between environmental and sociodemographic factors and Leptospira interrogans and Bartonella spp. infections in rats from Windsor, Ontario, Canada, while controlling for the potential confounding effects of animal characteristics (i.e., sexual maturity and body condition)., Methods and Results: Between November 2018 and June 2021, 252 rats were submitted by collaborating pest control professionals. Kidney and spleen samples were collected for L. interrogans and Bartonella spp. PCR and sequencing, respectively. Of the rats tested by PCR, 12.7% (32/252) were positive for L. interrogans and 16.3% (37/227) were positive for Bartonella species. Associations between infection status and environmental and sociodemographic variables of interest were assessed via mixed multivariable logistic regression models with a random intercept for social group and fixed effects to control for sexual maturity and body condition in each model. The odds of L. interrogans infection were significantly higher in rats from areas with high building density (odds ratio [OR]: 3.76; 95% CI: 1.31-10.79; p = 0.014), high human population density (OR: 3.31; 95% CI: 1.20-9.11; p = 0.021), high proportion of buildings built in 1960 or before (OR: 11.21; 95% CI: 2.06-60.89; p = 0.005), and a moderate number of reports of uncollected garbage compared to a low number of reports (OR: 4.88; 95% CI: 1.01-23.63; p = 0.049). A negative association was observed between median household income and Bartonella spp. infection in rats (OR: 0.26; 95% CI: 0.08-0.89; p = 0.031)., Conclusions: Due to the complexity of the ecology of rat-associated zoonoses, consideration of environmental and sociodemographic factors is of critical importance to better understand the nuances of host-pathogen systems and inform how urban rat surveillance and intervention efforts should be distributed within cities., (© 2024 The Authors. Zoonoses and Public Health published by Wiley‐VCH GmbH.)

Objectives: The aim of this study is to describe management and survival in adult patients with malignant ovarian germ cell tumors (MOGCT) undergoing surgery by general gynecologists (GG) versus gynecologic oncologists (GO)., Methods: This is a population-based retrospective cohort study, including patients (age ≥ 18 years old) with MOGCT identified in the provincial cancer registry of Ontario, (1996-2020). Baseline characteristics, surgical and chemotherapy treatment were compared between those with surgery by GG or GO. Cox proportional hazards (CPH) model was used to determine if surgeon specialty was associated with overall survival (OS)., Results: Overall, 363 patients were included. One-hundred and sixty (44%) underwent surgery by GO and 203 (56%) by GG. There were higher rates of stage II-IV in the GO group (27.5% vs 3.9%, p < 0.001, and higher proportion of chemotherapy (64.4% vs 37.4%, p < 0.0001). Five-year OS was 90% and 93% in the GO vs GG groups, respectively (p = 0.39). CPH model showed factors associated with increased risk of death were older age at diagnosis (HR 1.09, 95% CI 1.07-1.12) and chemotherapy (HR 3.12, 95% CI 1.44-6.75). Surgeon specialty was not independently associated with all-cause death (HR 1.04, 95% 0.51-2.15, p = 0.91)., Conclusions: In this group of MOGCT, 5-year OS was not significantly different between patients having surgery by GO compared to GG. Nevertheless, survival rates were lower than expected in the GG group despite their low-risk features. Further exploration is warranted regarding the reasons for this and whether patients with suspected MOGCT may benefit from early assessment by GO for optimal management., Competing Interests: Declaration of competing interest The authors report no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Type 1 diabetes (T1D) is a challenging chronic condition. Young children with T1D require daily support to manage their condition while at school. In 2018, Ontario established a provincial policy to ensure safe and equitable school participation for children with diabetes. Despite this, children and parents describe very different school experiences. In this qualitative study we describe the interpretation and implementation of school board policy related to the care of children with T1D from the perspective of school educators (principals/teachers)., Methods: Policy documents were reviewed employing a qualitative descriptive research design using directed qualitative content analysis. Semistructured interviews were conducted with 13 teachers and principals from 10 publicly funded elementary schools across the Hamilton and Toronto District School Boards in 2021., Results: There are major differences in how policies regarding T1D are being implemented in schools. This includes how school staff are educated about T1D, and how they interpret and act on blood glucose information. Although educators often play an active role in supporting children, many face barriers, including competing priorities, fear, lack of information, and lack of support. Facilitators include effective communication/collaboration, actionable information, time, and a diabetes "champion." In some instances, access to nursing support could help to resolve barriers or create care gaps., Conclusions: School board policy provides high-level guidance on how to support children with T1D in school, but gaps remain. We provide specific recommendations regarding policy, staff education/training, roles and responsibilities, and future research., (Copyright © 2024 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

The COVID-19 pandemic raised concerns regarding increased suicide-related behaviours. We compared characteristics and counts of Emergency Department (ED) presentations for self-harm, an important suicide-related outcome, during versus prior to the pandemic's first year. We included patients presenting with self-harm to the ED of two trauma centres in Toronto, Canada. Time series models compared intra-pandemic (March 2020-February 2021) presentation counts to predictions from pre-pandemic data. The self-harm proportion of ED presentations was compared between the intra-pandemic period and preceding three years. A retrospective chart review of eligible patients seen from March 2019-February 2021 compared pre- vs. intra-pandemic patient and injury characteristics. While monthly intra-pandemic self-harm counts were largely within expected ranges, the self-harm proportion of total presentations increased. Being widowed (OR=9.46; 95 %CI=1.10-81.08), employment/financial stressors (OR=1.65, 95 %CI=1.06-2.58), job loss (OR=3.83; 95 %CI=1.36-10.76), and chest-stabbing self-harm (OR=2.50; 95 %CI=1.16-5.39) were associated with intra-pandemic presentations. Intra-pandemic self-harm was also associated with Intensive Care Unit (ICU) admission (OR=2.18, 95 %CI=1.41-3.38). In summary, while the number of self-harm presentations to these trauma centres did not increase during the early pandemic, their proportion was increased. The association of intra-pandemic self-harm with variables indicating medically severe injury, economic stressors, and being widowed may inform future suicide and self-harm prevention strategies., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Objectives: This study's aims were to describe the outcomes of patients with diabetes presenting with their first ED visit for hyperglycemia, and to identify predictors of recurrent ED visits for hyperglycemia., Methods: Using linked databases, we conducted a population-based cohort study of adult and pediatric patients with types 1 and 2 diabetes presenting with a first ED visit for hyperglycemia from April 2010 to March 2020 in Ontario, Canada. We determined the proportion of patients with a recurrent ED visit for hyperglycemia within 30 days of the index visit. Using multivariable regression analysis, we examined clinical and socioeconomic predictors for recurrent visits., Results: There were 779,632 patients with a first ED visit for hyperglycemia. Mean (SD) age was 64.3 (15.2) years; 47.7% were female. 11.0% had a recurrent visit for hyperglycemia within 30 days. Statistically significant predictors of a recurrent visit included: male sex, type 1 diabetes, regions with fewer visible minority groups and with less education or employment, higher hemoglobin A1C, more family physician or internist visits within the past year, being rostered to a family physician, previous ED visits in the past year, ED or hospitalization within the previous 14 days, access to homecare services, and previous hyperglycemia encounters in the past 5 years. Alcoholism and depression or anxiety were positive predictors for the 18-65 age group., Conclusions: This population-level study identifies predictors of recurrent ED visits for hyperglycemia, including male sex, type 1 diabetes, regions with fewer visible minority groups and with less education or employment, higher hemoglobin A1C, higher previous healthcare system utilization (ED visits and hospitalization) for hyperglycemia, being rostered to a family physician, and access to homecare services. Knowledge of these predictors may be used to develop targeted interventions to improve patient outcomes and reduce healthcare system costs., (© 2024. The Author(s), under exclusive licence to Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

Purpose: The COVID-19 pandemic has resulted in a significant diagnostic, screening, and procedure backlog in Ontario. Engagement of key stakeholders in healthcare leadership positions is urgently needed to inform a comprehensive provincial recovery strategy., Methods: A list of 20 policy recommendations addressing the diagnostic, screening and procedure backlog in Ontario were transformed into a national online survey. Policy recommendations were rated on a 7-point Likert scale (strongly agree to strongly disagree) and organized into those retained (≥75% strongly agree to somewhat agree), discarded (≥80% somewhat disagree to strongly disagree), and no consensus reached. Survey participants included a diverse sample of healthcare leaders with the potential to impact policy reform., Results: Of 56 healthcare leaders invited to participate, there were 34 unique responses (61% response rate). Participants were from diverse clinical backgrounds, including surgical subspecialties, medicine, nursing, and healthcare administration and held institutional or provincial leadership positions. A total of 11 of 20 policy recommendations reached the threshold for consensus agreement with the remaining 9 having no consensus reached., Conclusion: Consensus agreement was reached among Canadian healthcare leaders on 11 policy recommendations to address the diagnostic, screening, and procedure backlog in Ontario. Recommendations included strategies to address patient information needs on expected wait times, expand health and human resource capacity, and streamline efficiencies to increase operating room output. No consensus was reached on the optimal funding strategy within the public system in Ontario or the appropriateness of implementing private funding models.

Objectives: International Classification of Diseases (ICD) codes are commonly used to identify cases of diabetic ketoacidosis (DKA) in health services research, but they have not been validated. Our aim in this study was to assess the accuracy of ICD, 10th revision (ICD-10) diagnosis codes for DKA., Methods: We conducted a multicentre, cross-sectional study using data from 5 hospitals in Ontario, Canada. Each hospitalization event has a single most responsible diagnosis code. We identified all hospitalizations assigned diagnosis codes for DKA. A true case of DKA was defined using laboratory values (serum bicarbonate ≤18 mmol/L, arterial pH ≤7.3, anion gap ≥14 mEq/L, and presence of ketones in urine or blood). Chart review was conducted to validate DKA if laboratory values were missing or the diagnosis of DKA was unclear. Outcome measures included positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of ICD-10 codes in patients with laboratory-defined DKA., Results: We identified 316,517 hospitalizations. Among these, 312,948 did not have an ICD-10 diagnosis code for DKA and 3,569 had an ICD-10 diagnosis code for DKA. Using a combination of laboratory and chart review, we identified that the overall PPV was 67.0%, the NPV was 99.7%, specificity was 99.6%, and sensitivity was 74.9%. When we restricted our analysis to hospitalizations in which DKA was the most responsible discharge diagnosis (n=3,374 [94.5%]), the test characteristics were PPV 69.8%, NPV 99.7%, specificity 99.7%, and sensitivity 71.9%., Conclusion: ICD-10 codes can identify patients with DKA among those admitted to general internal medicine., (Copyright © 2024 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

Introduction: We previously identified specific immigrant groups (West African and Caribbean) with increased incidence of prostate cancer in Ontario, Canada. In this population-level retrospective cohort study, we used administrative databases to compare stage of diagnosis, 5-year overall survival and prostate cancer-specific survival for immigrants versus long-term residents of Ontario., Methods: We linked several provincial-level databases available at ICES, an independent, non-profit research institute. We included all male Ontario residents 20-105 years of age who had an incident prostate cancer diagnosis date between March 31, 2008 and March 31, 2017, stratified into immigrants vs. long-term residents. We used multivariable logistic regression to determine the odds of early (stage I-II) vs. late (III-IV) stage of diagnosis, adjusting for age, co-morbidities, neighbourhood income and continuity of care. We produced Kaplan-Meier curves for 5-year overall survival and for 5-year prostate cancer-specific survival., Results: Compared to long-term residents, men from West Africa (adjusted odds ratio 1.66 [95% CI 1.16-2.38], East Africa (AOR 1.54 [95% CI 1.02-2.33]) and the Caribbean (AOR 1.22 [95% CI 1.01-1.47]) had a diagnostic stage advantage, and men from South Asia were most likely to be diagnosed at a late stage. In both unadjusted and adjusted analyses, overall and prostate cancer-specific survival were higher for immigrants than long-term residents. The highest five-year overall survival was seen for men from Sub-Saharan Africa and the Caribbean, and the lowest was seen for South Asian men, where 11.7% died within five years of diagnosis., Conclusion: Immigrant men in Ontario with prostate cancer are more likely to be diagnosed at an early stage and to survive for 5 years than long-term residents. Among immigrant men, men from the Caribbean and Sub-Saharan Africa have the greatest stage and survival advantage and South Asian men the least. Differences in awareness, diagnostic suspicion, genetic predisposition, and social factors may play a role in these findings., Competing Interests: Declaration of Competing Interest None, (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background and Aims: Behavioral economic theory predicts that high alcohol demand and high proportionate alcohol-related reinforcement are important determinants of risky alcohol use in emerging adults, but the majority of research to date has been cross-sectional in nature. The present study investigated prospective and dynamic relationships between alcohol demand and proportionate alcohol-related reinforcement in relation to heavy drinking days and alcohol problems., Design: Longitudinal cohort with assessments every 4 months for 20 months., Setting: Ontario, Canada., Participants: Emerging adults reporting regular heavy episodic drinking (n = 636, M age  = 21.44; 55.8% female)., Measurements: Heavy drinking days (HDD; Daily Drinking Questionnaire), alcohol problems (Brief Young Adult Alcohol Consequences Questionnaire), alcohol demand (Alcohol Purchase Task) and proportionate alcohol-related reinforcement (Activity Level Questionnaire)., Findings: Linear mixed effects models revealed that behavioral economic indicators and alcohol-related outcomes significantly decreased over the study, consistent with 'aging out' of risky alcohol use. Random intercept cross-lagged panel models revealed significant between-person relationships, such that higher alcohol demand and alcohol-related reinforcement were positively associated with HDD and alcohol problems (random intercepts = 0.187-0.534, Ps < 0.01). Moreover, alcohol demand indicators (particularly the rate of change in elasticity of the demand curve, as measured by α, and the maximum expenditure, O max ) and proportionate alcohol-related reinforcement significantly forecasted changes in HDD at all time points (|βs| = 0.063-0.103, Ps < 0.05) in cross-lagged relationships, with bidirectional associations noted for the rate of change in elasticity (βs = -0.085 to -0.104, Ps < 0.01). Proportionate alcohol-related reinforcement also significantly forecasted changes in alcohol problems at all time points (βs = 0.072-0.112, Ps < 0.01)., Conclusions: Multiple behavioral economic indicators (demand elasticity, maximum expenditure and reinforcement ratio) forecast changes in heavy episodic drinking and alcohol problems over the course of emerging adulthood. These results further implicate alcohol demand and proportionate alcohol-related reinforcement as etiologically and developmentally important mechanisms in alcohol use trajectories., (© 2024 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Objective: To examine changes in the prescribing of end-of-life symptom management medications in long-term care (LTC) homes during the COVID-19 pandemic., Design: Retrospective cohort study using routinely collected health administrative data in Ontario, Canada., Setting and Participants: We included all individuals who died in LTC homes between January 1, 2017, and March 31, 2021. We separated the study into 2 periods: before COVID-19 (January 1, 2017, to March 17, 2020) and during COVID-19 (March 18, 2020, to March 31, 2021)., Methods: For each LTC home, we measured the percentage of residents who died before and during COVID-19 who had a subcutaneous symptom management medication prescription in their last 14 days of life. We grouped LTC homes into quintiles based on their mean prescribing rates before COVID-19, and examined changes in prescribing during COVID-19 and COVID-19 outcomes across quintiles., Results: We captured 75,438 LTC residents who died in Ontario's 626 LTC homes during the entire study period, with 19,522 (25.9%) dying during COVID-19. The mean prescribing rate during COVID-19 ranged from 46.9% to 79.4% between the lowest and highest prescribing quintiles. During COVID-19, the mean prescribing rate in the lowest prescribing quintile increased by 9.6% compared to before COVID-19. Compared to LTC homes in the highest prescribing quintile, homes in the lowest prescribing quintile experienced the highest proportion of COVID-19 outbreaks (73.4% vs 50.0%), the largest mean outbreak intensity (0.27 vs 0.09 cases/bed), the highest mean total days with a COVID-19 outbreak (72.7 vs 24.2 days), and the greatest proportion of decedents who were transferred and died outside of LTC (22.1% vs 8.6%)., Conclusions and Implications: LTC homes in Ontario had wide variations in the prescribing rates of end-of-life symptom management medications before and during COVID-19. Homes in the lower prescribing quintiles had more COVID-19 cases per bed and days spent in an outbreak., Competing Interests: Disclosure The authors declare no conflicts of interest., (Copyright © 2024 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU)., Aim: To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission., Methods: This was a prospective cohort study of patients in six ICUs from 2018 to 2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial-resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples. All PA isolates underwent whole-genome sequencing. PA-HAI was defined using US National Healthcare Safety Network criteria. ICU-acquired PA was defined as PA isolated from specimens obtained ≥48 h after ICU admission in those with prior negative rectal swabs. Sink-to-patient PA transmission was defined as ICU-acquired PA with close genomic relationship to isolate(s) previously recovered from sinks in a room/bedspace occupied 3-14 days prior to collection date of the relevant patient specimen., Findings: Over ten months, 72 PA-HAIs occurred among 60/4263 admissions. The rate of PA-HAI was 2.40 per 1000 patient-ICU-days; higher in patients who were PA-colonized on admission. PA-HAI was associated with longer stay (median: 26 vs 3 days uninfected; P < 0.001) and contributed to death in 22/60 cases (36.7%). Fifty-eight admissions with ICU-acquired PA were identified, contributing 35/72 (48.6%) PA-HAIs. Four patients with five PA-HAIs (6.9%) had closely related isolates previously recovered from their room/bedspace sinks., Conclusion: Nearly half of PA causing HAI appeared to be acquired in ICUs, and 7% of PA-HAIs were associated with sink-to-patient transmission. Sinks may be an under-recognized reservoir for HAIs., (Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved.)

Background: The COVID-19 pandemic altered traffic patterns worldwide, potentially impacting pedestrian and bicyclists safety in urban areas. In Toronto, Canada, work from home policies, bicycle network expansion, and quiet streets were implemented to support walking and cycling. We examined pedestrian and bicyclist injury trends from 2012 to 2022, utilizing police-reported killed or severely injured (KSI), emergency department (ED) visits and hospitalization data., Methods: We used an interrupted time series design, with injury counts aggregated quarterly. We fit a negative binomial regression using a Bayesian modeling approach to data prior to the pandemic that included a secular time trend, quarterly seasonal indicator variables, and autoregressive terms. The differences between observed and expected injury counts based on pre-pandemic trends with 95% credible intervals (CIs) were computed., Results: There were 38% fewer pedestrian KSI (95%CI: 19%, 52%), 35% fewer ED visits (95%CI: 28%, 42%), and 19% fewer hospitalizations (95%CI: 2%, 32%) since the beginning of the COVID-19 pandemic. A reduction of 35% (95%CI: 7%, 54%) in KSI bicyclist injuries was observed, but However, ED visits and hospitalizations from bicycle-motor vehicle collisions were compatible with pre-pandemic trends. In contrast, for bicycle injuries not involving motor vehicles, large increases were observed for both ED visits, 73% (95% CI: 49%, 103%) and for hospitalization 108% (95% CI: 38%, 208%)., Conclusion: New road safety interventions during the pandemic may have improved road safety for vulnerable road users with respect to collisions with motor vehicles; however, further investigation into the risk factors for bicycle injuries not involving motor vehicles is required., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: Investigations about cesarean delivery (CD) on maternal request (CDMR) and infant infection risk frequently rely on administrative data with poorly defined indications for CD. We sought to determine the association between CDMR and infant infection using an intent-to-treat approach., Methods: This was a population-based cohort study of low-risk singleton pregnancies with a term live birth in Ontario, Canada between April 2012 and March 2018. Subjects with prior CD were excluded. Outcomes included upper and lower respiratory tract infections, gastrointestinal infections, otitis media, and a composite of these 4. Relative risk and 95% CI were calculated for component and composite outcomes up to 1 year following planned CDMR versus planned vaginal deliveries (VDs). Subgroup and sensitivity analyses included age at infection (≤28 vs. >28 days), type of care (ambulatory vs. hospitalisation), restricting the cohort to nulliparous pregnancies, and including individuals with previous CD. Last, we re-examined outcome risk on an as-treated basis (actual CD vs. actual VD)., Results: Of 422 134 pregnancies, 0.4% (1827) resulted in a planned CDMR. After adjusting for covariates, planned CDMR was not associated with a risk of composite infant infections (adjusted relative risk 1.02; 95% CI 0.92-1.11). Findings for component infection outcomes, subgroup, and sensitivity analyses were similar. However, the as-treated analysis of the role of delivery mode on infant risk for infection demonstrated that actual CD (planned and unplanned) was associated with an increased risk for infant infections compared to actual VD., Conclusions: Planned CDMR is not associated with increased risk for neonatal or infant infections compared with planned VD. Study design must be carefully considered when investigating the impact of CDMR on infant infection outcomes., (Copyright © 2024 The Author. Published by Elsevier Inc. All rights reserved.)

Background: Patients with chronic hepatitis C (CHC) can be cured with the new highly effective interferon-free combination treatments (DAA) that were approved in 2014. However, CHC is a largely silent disease, and many individuals are unaware of their infections until the late stages of the disease. The impact of wider access to effective treatments and improved awareness of the disease on the number of infections and the number of patients who remain undiagnosed is not known in Canada. Such evidence can guide the development of strategies and interventions to reduce the burden of CHC and meet World Health Organization's (WHO) 2030 elimination targets. The purpose of this study is to use a back-calculation framework informed by provincial population-level health administrative data to estimate the prevalence of CHC and the proportion of cases that remain undiagnosed in the three most populated provinces in Canada: British Columbia (BC), Ontario and Quebec., Methods: We have conducted a population-based retrospective analysis of health administrative data for the three provinces to generate the annual incidence of newly diagnosed CHC cases, decompensated cirrhosis (DC), hepatocellular carcinoma (HCC) and HCV treatment initiations. For each province, the data were stratified in three birth cohorts: individuals born prior to 1945, individuals born between 1945 and 1965 and individuals born after 1965. We used a back-calculation modelling approach to estimate prevalence and the undiagnosed proportion of CHC. The historical prevalence of CHC was inferred through a calibration process based on a Bayesian Markov chain Monte Carlo (MCMC) algorithm. The algorithm constructs the historical prevalence of CHC for each cohort by comparing the model-generated outcomes of the annual incidence of the CHC-related health events against the data set of observed diagnosed cases generated in the retrospective analysis., Results: The results show a decreasing trend in both CHC prevalence and undiagnosed proportion in BC, Ontario and Quebec. In 2018, CHC prevalence was estimated to be 1.23% (95% CI: .96%-1.62%), .91% (95% CI: .82%-1.04%) and .57% (95% CI: .51%-.64%) in BC, Ontario and Quebec respectively. The CHC undiagnosed proportion was assessed to be 35.44% (95% CI: 27.07%-45.83%), 34.28% (95% CI: 26.74%-41.62%) and 46.32% (95% CI: 37.85%-52.80%) in BC, Ontario and Quebec, respectively, in 2018. Also, since the introduction of new DAA treatment in 2014, CHC prevalence decreased from 1.39% to 1.23%, .97% to .91% and .65% to .57% in BC, Ontario and Quebec respectively. Similarly, the CHC undiagnosed proportion decreased from 38.78% to 35.44%, 38.70% to 34.28% and 47.54% to 46.32% in BC, Ontario and Quebec, respectively, from 2014 to 2018., Conclusions: We estimated that the CHC prevalence and undiagnosed proportion have declined for all three provinces since the new DAA treatment has been approved in 2014. Yet, our findings show that a significant proportion of HCV cases remain undiagnosed across all provinces highlighting the need to increase investment in screening. Our findings provide essential evidence to guide decisions about current and future HCV strategies and help achieve the WHO goal of eliminating hepatitis C in Canada by 2030., (© 2024 The Authors. Liver International published by John Wiley & Sons Ltd.)

Background: Endometriosis is a chronic gynecologic disorder that leads to considerable pain and a reduced quality of life. Although its physiological manifestations have been explored, its impact on mental health is less well defined. Existing studies of endometriosis and mental health were conducted within diverse healthcare landscapes with varying access to care and with a primary focus on surgically diagnosed endometriosis. A single-payer healthcare system offers a unique environment to investigate this association with fewer barriers to access care while considering the mode of endometriosis diagnosis., Objective: Our objective was to assess the association between endometriosis and the risk for mental health conditions and to evaluate differences between patients diagnosed medically and those diagnosed surgically., Study Design: A matched, population-based retrospective cohort study was conducted in Ontario and included patients aged 18 to 50 years with a first-time endometriosis diagnosis between January 1, 2010, and July 1, 2020. Endometriosis exposure was determined through either medical or surgical diagnostic criteria. A medical diagnosis was defined by the use of the corresponding International Classification of Disease diagnostic codes from outpatient and in-hospital visits, whereas a surgical diagnosis was identified through inpatient or same-day surgeries. Individuals with endometriosis were matched 1:2 on age, sex, and geography to unexposed individuals without a history of endometriosis. The primary outcome was the first occurrence of any mental health condition after an endometriosis diagnosis. Individuals with a mental health diagnosis in the 2 years before study entry were excluded. Cox regression models were used to generate hazard ratios with adjustment for hysterectomy, salpingo-oophorectomy, infertility, pregnancy history, qualifying surgery for study inclusion, immigration status, history of asthma, abnormal uterine bleeding, diabetes, fibroids, hypertension, irritable bowel disorder, migraines, and nulliparity., Results: A total of 107,832 individuals were included, 35,944 with a diagnosis of endometriosis (29.5% medically diagnosed, 60.5% surgically diagnosed, and 10.0% medically diagnosed with surgical confirmation) and 71,888 unexposed individuals. Over the study period, the incidence rate was 105.3 mental health events per 1000 person-years in the endometriosis group and 66.5 mental health events per 1000 person-year among unexposed individuals. Relative to the unexposed individuals, the adjusted hazard ratio for a mental health diagnosis was 1.28 (95% confidence interval, 1.24-1.33) among patients with medically diagnosed endometriosis, 1.33 (95% confidence interval, 1.16-1.52) among surgically diagnosed patients, and 1.36 (95% confidence interval, 1.2-1.6) among those diagnosed medically with subsequent surgical confirmation. The risk for receiving a mental health diagnosis was highest in the first year after an endometriosis diagnosis and declined in subsequent years. The cumulative incidence of a severe mental health condition requiring hospital visits was 7.0% among patients with endometriosis and 4.6% among unexposed individuals (hazard ratio, 1.56; 95% confidence interval, 1.53-1.59)., Conclusion: Endometriosis, regardless of mode of diagnosis, is associated with a marginally increased risk for mental health conditions. The elevated risk, particularly evident in the years immediately following the diagnosis, underscores the need for proactive mental health screening among those newly diagnosed with endometriosis. Future research should investigate the potential benefits of mental health interventions for people with endometriosis with the aim of enhancing their overall quality of life., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objectives: International infectious disease/obstetrical societies have recently recommended universal hepatitis C virus (HCV) prenatal screening and these same recommendations are forthcoming in Canada. At present, there is no formal analysis of universal HCV screening or linkage to care of pregnant people in Ontario. The objectives of our study were to determine the seroprevalence of HCV using 2 different methods to evaluate universal screening, as well as identify opportunities that may improve linkage to care., Methods: To assess seroprevalence in a large urban area, we aimed to test 12 000 de-identified samples submitted for prenatal HIV testing in the catchment area of Toronto Public Health for HCV antibodies. Then, to assess the seroprevalence as well as the operational impact and follow-up in a real-world setting, we completed a Quality Improvement Project (QIP) for 1 year at a large tertiary care obstetrical centre in London, Ontario., Results: From 2019 to 2021, 11 999 de-identified samples were screened from Toronto with a seroprevalence of 0.40 (95% CI 0.29-0.53). In London, 5771 people were screened in 2021 with a seroprevalence of 0.55% (95% CI 0.38-0.78). Taken together, those aged 26-35 years had the highest positivity; in the QIP, 9% had no documented risk factor, and 59% of individuals were not linked to the next step in HCV care., Conclusions: HCV prenatal seroprevalence in Ontario is comparable to hepatitis B virus, and ∼15-30-fold higher than HIV. Diagnosis in pregnancy is critical to facilitate referrals for treatment between pregnancies and could increase screening among children born to positive women., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Purpose: Cardiogenic shock secondary to acute myocardial infarction (AMI-CS) is associated with substantial short- and long-term morbidity and mortality. However, there are limited data on mental health sequelae that survivors experience following discharge., Methods: We conducted a retrospective, population-based cohort study in Ontario, Canada of critically ill adult (≥ 18 years) survivors of AMI-CS, admitted to hospital between April 1, 2009 and March 31, 2019. We compared these patients to AMI survivors without shock. We captured outcome data using linked health administrative databases. The primary outcome was a new mental health diagnosis (a composite of mood, anxiety, or related disorders; schizophrenia/psychotic disorders; and other mental health disorders) following hospital discharge. We secondarily evaluated incidence of deliberate self-harm and death by suicide. We compared patients using overlap propensity score-weighted, cause-specific proportional hazard models., Results: We included 7812 consecutive survivors of AMI-CS, from 135 centers. Mean age was 68.4 (standard deviation (SD) 12.2) years, and 70.3% were male. Median follow-up time was 767 days (interquartile range (IQR) 225-1682). Incidence of new mental health diagnosis among AMI-CS survivors was 109.6 per 1,000 person-years (95% confidence interval (CI) 105.4-113.9), compared with 103.8 per 1000 person-years (95% CI 102.5-105.2) among AMI survivors without shock. After propensity score adjustment, there was no difference in the risk of new mental health diagnoses following discharge [hazard ratio (HR) 0.99 (95% CI 0.94-1.03)]. Factors associated with new mental health diagnoses following AMI-CS included female sex, pre-existing mental health diagnoses, and discharge to a long-term hospital or rehabilitation institute., Conclusion: Survivors of AMI-CS experience substantial mental health morbidity following discharge. Risk of new mental health diagnoses was comparable between survivors of AMI with and without shock. Future research on interventions to mitigate psychiatric sequelae after AMI-CS is warranted., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: Pediatric esophageal foreign bodies (EFBs) are common and can result in serious complications. Little is known about the influence of socioeconomic status (SES) on EFB ingestion in children. The goal was to study SES as a risk factor for dangerous foreign body ingestion and in-hospital complications in children., Methods: This was a retrospective cohort study of children presenting to a tertiary care pediatric hospital with an esophageal foreign body from 2010 to 2021. SES was assessed for each patient by linking their postal code to the Ontario Marginalization Index to determine a quintile score across four dimensions of deprivation: residential instability, material deprivation, dependency, and ethnic concentration. Dangerous EFBs were defined as magnets, batteries, sharp objects, or bones. In-hospital complications included: intensive care unit admission, prolonged length of stay, and postoperative sequelae., Results: A total of 680 patients were included. Dangerous EFB ingestion was higher for children with increased residential instability (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.2-3.6) and increased material deprivation (OR, 2.2; CI, 1.9-2.8), which was similarly true for odds of complications. Odds of dangerous EFB ingestion were higher in older children (OR, 1.1; CI, 1.0-1.1) and odds of complications were higher in children with comorbidities (OR, 1.1; CI, 1.0-1.3)., Conclusion: Higher levels of housing instability and material deprivation are associated with dangerous EFB ingestion and complications related to EFB ingestion. These findings emphasize the role that SES plays on child health outcomes and the need for initiatives to mitigate these disparities., Level of Evidence: 3 Laryngoscope, 134:2945-2953, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)

Background and Aims: Identifying effective opioid treatment options during pregnancy is a high priority due to the growing prevalence of opioid use disorder across North America. We assessed the temporal impact of three population-level interventions on the use of opioid agonist treatment (OAT) during pregnancy in Ontario, Canada., Design: This was a population-based time-series analysis to identify trends in the monthly prevalence of pregnant people dispensed methadone and buprenorphine. The impact of adding buprenorphine/naloxone to the public drug formulary, the release of pregnancy-specific guidance and the start of the COVID-19 pandemic were assessed., Setting and Participants: The study was conducted in Ontario, Canada between 1 July 2013 and 31 March 2022, comprising people who delivered a live or stillbirth in any Ontario hospital during the study period., Measurements: We identified any prescription for methadone or buprenorphine dispensed between the estimated conception date and delivery date and calculated the monthly prevalence of OAT-exposed pregnancies among all pregnant people in Ontario., Findings: Overall, rates of OAT during pregnancy have declined since mid-2018. Methadone-exposed pregnancies decreased from 0.46% of all pregnancies in Ontario in 2015 to a low of 0.16% in 2022. In the primary analysis, none of the interventions had a statistically significant impact on overall OAT rates; however, in the stratified analyses, there was a small increase in buprenorphine after the formulary change [0.006%, 95% confidence interval (CI) = 0.0032-0.0081, P < 0.0001] and a decrease in buprenorphine after the release of the 2017 guidelines (-0.005%, 95% CI = -0.0080 to -0.0020, P = 0.001) and the start of the COVID-19 pandemic (-0.003%, 95% CI = -0.0054 to -0.0006, P = 0.015)., Conclusion: Despite changes in guidance and funding, opioid agonist treatment during pregnancy has been declining in Ontario, Canada since 2018., (© 2024 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Objectives: Health administrative data can be used to improve the health of people who inject drugs by informing public health surveillance and program planning, monitoring, and evaluation. However, methodological gaps in the use of these data persist due to challenges in accurately identifying injection drug use (IDU) at the population level. In this study, we validated case-ascertainment algorithms for identifying people who inject drugs using health administrative data in Ontario, Canada., Study Design and Setting: Data from cohorts of people with recent (past 12 months) IDU, including those participating in community-based research studies or seeking drug treatment, were linked to health administrative data in Ontario from 1992 to 2020. We assessed the validity of algorithms to identify IDU over varying look-back periods (ie, all years of data [1992 onwards] or within the past 1-5 years), including inpatient and outpatient physician billing claims for drug use, emergency department (ED) visits or hospitalizations for drug use or injection-related infections, and opioid agonist treatment (OAT)., Results: Algorithms were validated using data from 15,241 people with recent IDU (918 in community cohorts and 14,323 seeking drug treatment). An algorithm consisting of ≥1 physician visit, ED visit, or hospitalization for drug use, or OAT record could effectively identify IDU history (91.6% sensitivity and 94.2% specificity) and recent IDU (using 3-year look back: 80.4% sensitivity, 99% specificity) among community cohorts. Algorithms were generally more sensitive among people who inject drugs seeking drug treatment., Conclusion: Validated algorithms using health administrative data performed well in identifying people who inject drugs. Despite their high sensitivity and specificity, the positive predictive value of these algorithms will vary depending on the underlying prevalence of IDU in the population in which they are applied., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr Jordan Feld has received research support from AbbVie Inc and Gilead Sciences for matters unrelated to the current study. Dr Eric Benchimol has acted as a consultant for McKesson Canada, the Dairy Farmers of Ontario and the Canadian Agency for Drugs and Technology in Health (CADTH) for matters unrelated to the topic of this research or to this study. Dr Sofia Bartlett has consulted, participated in advisory boards, and spoken for AbbVie Inc., Gilead Sciences Canada, Inc. and Cepheid Inc. for matters unrelated to the current study, and no personal payments were accepted. Dr Naveed Janjua has participated in advisory boards and has spoken for AbbVie and Gilead, for matters unrelated to the current study. All other coauthors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Background: Guidelines recommend that patients with melanoma undergo dermatologic examination at least annually. Adherence to follow-up and its impact on survival are unclear., Objective: To determine the level of adherence to annual dermatologic follow-up in patients with primary cutaneous melanoma, identify predictors for better adherence, and evaluate whether adherence was associated with melanoma-related mortality., Methods: Retrospective inception cohort analysis of adults with primary invasive melanoma in Ontario, Canada from 2010 to 2013 with follow-up until December 31, 2018., Results: Adherence to dermatologic follow-up was variable with only 28.0% of patients seeing a dermatologist at least annually (median follow-up 5.0 years). Younger age, female sex, higher income, greater access to dermatology care, stage 2/3 melanoma, prior keratinocyte carcinoma, fewer comorbidities, and any outpatient visit in the 12 months prior to melanoma diagnosis were predictors for adherence. Greater adherence to annual dermatology visits was associated with reduced melanoma-specific mortality compared with lower levels of adherence (adjusted hazard ratio 0.64, 95% CI 0.52-0.78)., Limitations: Observational study design and inability to identify skin examinations performed by non-dermatologists., Conclusion: Adherence to annual dermatology visits after melanoma diagnosis was low. Greater adherence may promote better patient survival but warrants confirmation in further research including randomized trials., Competing Interests: Conflicts of interest Dr Fleming has received honorarium and/or consulting and/or advisory boards and/or speaking fees and/or been an investigator for AbbVie, Altius, Amgen, Aralez, Bausch Health, Cipher, Galderma, Eli Lilly, L'Oreal, UCB, Janssen, Medexus Pharmaceuticals, Novartis, Pfizer and Sanofi-Genzyme, and Sun Pharma for work unrelated to this manuscript; Dr Huang has received honorarium or advisory board consulting fees for AbbVie, Novartis, UCB, CeraVe, Galderma, and Sanofi for work unrelated to this manuscript. Author Fung and Dr Chan have no conflicts of interest to declare., (Copyright © 2024 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Background and Aims: There is an incomplete understanding of the full safety profiles of repeated COVID-19 vaccinations in patients with inflammatory bowel disease (IBD). Among individuals with IBD, we assessed whether COVID-19 vaccines were associated with serious adverse events of special interest (AESI) and health care utilization [all-cause hospitalizations, Emergency Department (ED) visits, gastroenterology visits, IBD-related visits]., Methods: Using comprehensive administrative health data from Ontario, Canada, adults with IBD who received at least one COVID-19 vaccine from December 2020-January 2022 were included. Self-controlled case series analyses were conducted to evaluate the relative incidence rates of AESI and health care utilization outcomes across post-vaccination risk and control periods., Results: Among 88,407 IBD patients, 99.7% received mRNA vaccines and 75.9% received ≥ 3 doses. Relative to control periods, we did not detect an increase in AESI. IBD patients had fewer all-cause hospitalizations during post-vaccination risk periods. Patients experienced more all-cause ED visits after dose 2 [Relative Incidence (RI):1.08(95%CI:1.04-1.12)] but fewer visits after doses 3 [RI:0.85 (95%CI:0.81-0.90)] and 4 [RI:0.73 (95%CI:0.57-0.92)]. There was no increase in gastroenterologist visits or IBD-related health care utilization post-vaccination. There were fewer IBD-related hospitalizations after dose 1 [RI:0.84 (95%CI:0.72-0.98)] and 3 [RI:0.63 (95%CI:0.52-0.76)], fewer IBD-related ED visits after dose 3 [RI:0.81 (95%CI:0.71-0.91)] and 4 [RI:0.55 (95%CI:0.32-0.96)], and fewer outpatient visits after dose 2 [RI:0.91 (95%CI:0.90-0.93)] and 3 [RI:0.87 (95%CI:0.86-0.89)]., Conclusion: This population-based study did not detect increased AESI, all-cause or IBD-related health care utilization following COVID-19 vaccination, suggesting a lack of association between vaccination and increased disease activity., (© 2024. The Author(s).)

Purpose: Patients with lung cancer can experience significant psychological morbidities including depression. We characterize patterns and factors associated with interventions for symptoms of depression in stage IV non-small cell lung cancer (NSCLC)., Methods: We conducted a population-based cohort study using health services administrative data in Ontario, Canada of stage IV NSCLC diagnosed from January 2007 to September 2018. A positive symptom of depression score was defined by reporting at least one ESAS (Edmonton Symptom Assessment System) depression score ≥ 2 following diagnosis until the end of follow-up (September 2019). Patient factors included age, sex, comorbidity burden, rurality of residence, and neighbourhood income quintile. Interventions included psychiatry assessment, psychology referral, social work referral and anti-depressant medical therapy (for patients ≥ 65 years with universal drug coverage). Multivariable modified Poisson regression models were used to examine the association between patient factors and intervention use for patients who reported symptoms of depression., Results: In the cohort of 13,159 patients with stage IV NSCLC lung cancer, symptoms of depression were prevalent (71.4%, n = 9,397). Patients who reported symptoms of depression were more likely to receive psychiatry assessment/psychology referral (7.8% vs 3.5%; SD [standardized difference] 0.19), social work referral (17.4% vs 11.9%; SD 0.16) and anti-depressant prescriptions (23.8% vs 13.8%; SD 0.26) when compared to patients who did not report symptoms of depression respectively. In multivariable analyses, older patients were less likely to receive any intervention. Females were more likely to obtain a psychiatry assessment/psychology referral or social work referral. In addition, patients from non-major urban or rural residences were less likely to receive psychiatry assessment/psychology referral or social work referral, however patients from rural residences were more likely to be prescribed anti-depressants., Conclusions: There is high prevalence of symptoms of depression in stage IV NSCLC. We identify patient populations, including older patients and rural patients, who are less likely to receive interventions that will help identifying and screening for symptoms of depression., (© 2024. Crown.)

Classroom and staffroom floor swabs across six elementary schools in Ottawa, Canada were tested for SARS-CoV-2. Environmental test positivity did not correlate with student grade groups, school-level absenteeism, pediatric COVID-19-related hospitalizations, or community SARS-CoV-2 wastewater levels. Schools in neighbourhoods with historically elevated COVID-19 burden showed a negative but non-significant association with lower swab positivity., Competing Interests: ED works for DNA Genotek that provided sampling swabs in-kind for this study in an unrestricted fashion. DNA Genotek had no control over the findings, interpretations, or conclusions published in this paper. MF is a consultant for ProofDx, a start-up company that has created a point of care testing device for adults with COVID-19 using CRISPR. DM is a consultant for wastewater surveillance, World Bank. All other authors have no relevant conflicts to disclose. “This does not alter our adherence to PLOS ONE policies on sharing data and materials.”, (Copyright: © 2024 Thampi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Several epidemiological studies have investigated the possible role that living in areas with greater amounts of greenspace has on the incidence of childhood asthma. These findings have been inconsistent, and few studies explored the relevance of timing of exposure. We investigated the role of residential surrounding greenness on the risk of incident asthma using a population-based retrospective cohort study. We included 982,131 singleton births in Ontario, Canada between 2006 and 2013. Two measures of greenness, the Normalized Difference Vegetation Index (NDVI) and the Green View Index (GVI), were assigned to the residential histories of these infants from pregnancy through to 12 years of age. Longitudinally-based diagnoses of asthma were determined by using provincial administrative health data. The extended Cox hazards model was used to characterize associations between greenness measures and asthma (up to age 12 years) while adjusting for several risk factors. In a fully adjusted model, that included a term for traffic-related air pollution (NO 2 ), we found no association between an interquartile range increase (0.08) of the NDVI during childhood and asthma incidence (HR = 0.99; 95 % CI = 0.99-1.01). In contrast, we found that an 0.08 increase in NDVI during childhood reduced the risk of asthma in children 7-12 years of age by 14 % (HR = 0.86, 95 % CI:0.79-0.95). Seasonal differences in the association between greenness and asthma were noted. Our findings suggest that residential proximity to greenness reduces the risk of asthma in children aged 7-12., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Introduction: We assessed protection from coronavirus disease 2019 (COVID-19) vaccines and/or prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection against Omicron-associated severe outcomes during successive sublineage-predominant periods., Methods: We used a test-negative design to estimate protection by vaccines and/or prior infection against hospitalization/death among community-dwelling, polymerase chain reaction (PCR)-tested adults aged ≥50 years in Ontario, Canada, between 2 January 2022 and 30 June 2023. Multivariable logistic regression was used to estimate the relative change in the odds of hospitalization/death with each vaccine dose (2-5) and/or prior PCR-confirmed SARS-CoV-2 infection (compared with unvaccinated, uninfected subjects) up to 15 months since the last vaccination or infection., Results: We included 18 526 cases with Omicron-associated severe outcomes and 90 778 test-negative controls. Vaccine protection was high during BA.1/BA.2 predominance but was generally <50% during periods of BA.4/BA.5 and BQ/XBB predominance without boosters. A third/fourth dose transiently increased protection during BA.4/BA.5 predominance (third-dose, 6-month: 68%, 95% confidence interval [CI] 63%-72%; fourth-dose, 6-month: 80%, 95% CI 77%-83%) but was lower and waned quickly during BQ/XBB predominance (third-dose, 6-month: 59%, 95% CI 48%-67%; 12-month: 49%, 95% CI 41%-56%; fourth-dose, 6-month: 62%, 95% CI 56%-68%, 12-months: 51%, 95% CI 41%-56%). Hybrid immunity conferred nearly 90% protection throughout BA.1/BA.2 and BA.4/BA.5 predominance but was reduced during BQ/XBB predominance (third-dose, 6-month: 60%, 95% CI 36%-75%; fourth-dose, 6-month: 63%, 95% CI 42%-76%). Protection was restored with a fifth dose (bivalent; 6-month: 91%, 95% CI 79%-96%). Prior infection alone did not confer lasting protection., Conclusions: Protection from COVID-19 vaccines and/or prior SARS-CoV-2 infections against severe outcomes is reduced when immune-evasive variants/subvariants emerge and may also wane over time. Our findings support a variant-adapted booster vaccination strategy with periodic review., Competing Interests: Potential conflicts of interest. N. L. has previously received honoraria for consultancy work, speaking in educational programs, and/or travel support from: Shionogi Inc., Gilead Sciences Canada Inc., Janssen Inc., GlaxoSmithKline plc., Sanofi Pasteur Ltd., F. Hoffmann-La Roche Ltd., Genentech Inc., CIDARA Therapeutics Inc., Clarion Healthcare, bioStrategies, Technospert, Aligos; all unrelated to this work. K. W. is a shareholder and board member and Co-founder and Chief Scientific Officer of CANImmunize Inc. and has served on independent scientific advisory boards for Medicago (Independent Data Monitoring Committee) and Moderna (Global Advisory Core Consultancy Group). J. G. reports a position as a paid consultant scientific editor for GIDEON Informatics, Inc., which is unrelated to the current work. S. E. W. reports being a co-investigator on a grant related to public health surveillance of invasive pneumococcal disease (no involvement in administration of funds) for the Canadian Immunization Research Network and a co-investigator on a grant on immunization data in Canada (no involvement in administration of funds) for CIRN; travel support to attend the Future of Vaccinology conference in October 2023 as an invited speaker from McMaster University (Hamilton, ON) and a role as an unpaid volunteer member for Canada's National Advisory Committee on Immunization (NACI). All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Delirium is a major cause of preventable mortality and morbidity in hospitalized adults, but accurately determining rates of delirium remains a challenge., Objective: To characterize and compare medical inpatients identified as having delirium using two common methods, administrative data and retrospective chart review., Methods: We conducted a retrospective study of 3881 randomly selected internal medicine hospital admissions from six acute care hospitals in Toronto and Mississauga, Ontario, Canada. Delirium status was determined using ICD-10-CA codes from hospital administrative data and through a previously validated chart review method. Baseline sociodemographic and clinical characteristics, processes of care and outcomes were compared across those without delirium in hospital and those with delirium as determined by administrative data and chart review., Results: Delirium was identified in 6.3% of admissions by ICD-10-CA codes compared to 25.7% by chart review. Using chart review as the reference standard, ICD-10-CA codes for delirium had sensitivity 24.1% (95%CI: 21.5-26.8%), specificity 99.8% (95%CI: 99.5-99.9%), positive predictive value 97.6% (95%CI: 94.6-98.9%), and negative predictive value 79.2% (95%CI: 78.6-79.7%). Age over 80, male gender, and Charlson comorbidity index greater than 2 were associated with misclassification of delirium. Inpatient mortality and median costs of care were greater in patients determined to have delirium by ICD-10-CA codes (5.8% greater mortality, 95% CI: 2.0-9.5 and $6824 greater cost, 95%CI: 4713-9264) and by chart review (11.9% greater mortality, 95%CI: 9.5-14.2% and $4967 greater cost, 95%CI: 4415-5701), compared to patients without delirium., Conclusions: Administrative data are specific but highly insensitive, missing most cases of delirium in hospital. Mortality and costs of care were greater for both the delirium cases that were detected and missed by administrative data. Better methods of routinely measuring delirium in hospital are needed., Competing Interests: Fahad Razak and Amol Verma are employees of Ontario Health. The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding sources. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2024 Sheehan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Evidence suggests that for low-risk pregnancies, planned home births attended by a skilled health professional in settings where such services are well integrated are associated with lower risk of intrapartum interventions and no increase in adverse health outcomes. Monitoring and updating evidence on the safety of planned home births is necessary to inform ongoing clinical and policy decisions., Methods: This protocol describes a population-based retrospective cohort study which aims to compare risk of (a) neonatal morbidity and mortality, and (b) maternal outcomes and birth interventions, between people at low obstetrical risk with a planned home birth with a midwife, a planned a hospital birth with a midwife, or a planned hospital birth with a physician. The study population will include Ontario residents who gave birth in Ontario, Canada between April 1, 2012, and March 31, 2021. We will use data collected prospectively in a provincial perinatal data registry. The primary outcome will be severe neonatal morbidity or mortality, a composite binary outcome that includes one or more of the following conditions: stillbirth during the intrapartum period, neonatal death (death of a liveborn infant in the first 28 completed days of life), five-minute Apgar score <4, or infant resuscitation requiring cardiac compressions. We will conduct a stratified analysis with three strata: nulliparous, parous-no previous caesarean birth, and parous-prior caesarean birth. To reduce the impact of selection bias in estimating the effect of planned place of birth on neonatal and maternal outcomes, we will use propensity score (PS) overlap weighting (OW) and modified Poisson regression to conduct multivariate analyses., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Darling et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: The public health measures associated with the COVID-19 pandemic may have indirectly impacted other health outcomes, such as falls among older adults. The purpose of this study was to examine trends in fall-related hospitalizations and emergency department visits among older adults before and during the COVID-19 pandemic in Ontario, Canada., Methods: We obtained fall-related hospitalizations (N = 301,945) and emergency department visit (N = 1,150,829) data from the Canadian Institute for Health Information databases from 2015 to 2022 for adults ages 65 and older in Ontario. Fall-related injuries were obtained using International Classification of Diseases, 10th edition, Canada codes. An interrupted time series analysis was used to model the change in weekly fall-related hospitalizations and emergency department visits before (January 6, 2015-March 16, 2020) and during (March 17, 2020-December 26, 2022) the pandemic., Results: After adjusting for seasonality and population changes, an 8% decrease in fall-related hospitalizations [Relative Rate (RR) = 0.92, 95% Confidence Interval (CI): 0.85, 1.00] and a 23% decrease in fall-related emergency department visits (RR = 0.77, 95%CI: 0.59, 1.00) were observed immediately following the onset of the pandemic, followed by increasing trends during the pandemic for both outcomes., Conclusions: Following an abrupt decrease in hospitalizations and emergency department visits immediately following the onset of the pandemic, fall-related hospitalizations and emergency department visits have been increasing steadily and are approaching pre-pandemic levels. Further research exploring the factors contributing to these trends may inform future policies for public health emergencies that balance limiting the spread of disease among this population while supporting the physical, psychological, and social needs of this vulnerable group., (© 2024. Crown.)

There is lack of clarity on whether pregnancies during COVID-19 resulted in poorer mode of delivery and birth outcomes in Ontario, Canada. We aimed to compare mode of delivery (C-section), birth (low birthweight, preterm birth, NICU admission), and health services use (HSU, hospitalizations, ED visits, physician visits) outcomes in pregnant Ontario women before and during COVID-19 (pandemic periods). We further stratified for pre-existing chronic diseases (asthma, eczema, allergic rhinitis, diabetes, hypertension). Deliveries before (Jun 2018-Feb 2020) and during (Jul 2020-Mar 2022) pandemic were from health administrative data. We used multivariable logistic regression analyses to estimate adjusted odds ratios (aOR) of delivery and birth outcomes, and negative binomial regression for adjusted rate ratios (aRR) of HSU. We compared outcomes between pre-pandemic and pandemic periods. Possible interactions between study periods and covariates were also examined. 323,359 deliveries were included (50% during pandemic). One in 5 (18.3%) women who delivered during the pandemic had not received any COVID-19 vaccine, while one in 20 women (5.2%) lab-tested positive for COVID-19. The odds of C-section delivery during the pandemic was 9% higher (aOR = 1.09, 95% CI: 1.08-1.11) than pre-pandemic. The odds of preterm birth and NICU admission were 15% (aOR = 0.85, 95% CI: 0.82-0.87) and 10% lower (aOR = 0.90, 95% CI: 0.88-0.92), respectively, during COVID-19. There was a 17% reduction in ED visits but a 16% increase in physician visits during the pandemic (aRR = 0.83, 95% CI: 0.81-0.84 and aRR = 1.16, 95% CI: 1.16-1.17, respectively). These aORs and aRRs were significantly higher in women with pre-existing chronic conditions. During the pandemic, healthcare utilization, especially ED visits (aRR = 0.83), in pregnant women was lower compared to before. Ensuring ongoing prenatal care during the pandemic may reduce risks of adverse mode of delivery and the need for acute care during pregnancy., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 To et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Immigrants and refugees face unique challenges navigating the health care system to manage severe arthritis, because of unfamiliarity, lack of awareness of surgical options, or access. The purpose of this study was to assess total knee arthroplasty (TKA) uptake, surgical outcomes, and hospital utilization among immigrants and refugees compared with Canadian-born patients., Methods: We included all adults undergoing primary TKA from January 2011 to December 2020 in Ontario. Cohorts were defined as Canadian-born or immigrants and refugees. We assessed change in yearly TKA utilization for trend. We compared differences in 1-year revision, infection rates, 30-day venous thromboembolism (VTE), presentation to emergency department, and hospital readmission between matched Canadian-born and immigrant and refugee groups., Results: We included 158 031 TKA procedures. A total of 11 973 (7.6%) patients were in the immigrant and refugee group, and 146 058 (92.4%) patients were in the Canadian-born group. The proportion of TKAs in Ontario performed among immigrants and refugees nearly doubled over the 10-year study period ( p < 0.001). After matching, immigrants were at relatively lower risk of 1-year revision (0.9% v. 1.6%, p < 0.001), infection ( p < 0.001), death ( p = 0.004), and surgical complications ( p < 0.001). No differences were observed in rates of 30-day VTE or length of hospital stay. Immigrants were more likely to be discharged to rehabilitation ( p < 0.001) and less likely to present to the emergency department ( p < 0.001) than Canadian-born patients., Conclusion: Compared with Canadian-born patients, immigrants and refugees have favourable surgical outcomes and similar rates of resource utilization after TKA. We observed an underutilization of these procedures in Ontario relative to their proportion of the population. This may reflect differences in perceptions of chronic pain or barriers accessing arthroplasty., Competing Interests: Competing interests:: J. Michael Paterson reports research funding from Arthritis Society Canada and the Canadian Institutes of Health Research. No other competing interests were declared., (© 2024 CMA Impact Inc. or its licensors.)

Introduction: The study aimed to correlate the history of intravesical BCG as well as infantile BCG immunization with the incidence and severity of COVID-19 infection., Methods: Retrospective data collection of patients with high-risk non muscle invasive bladder cancer (NMIBC) from two Canadian centers. Data collection included a history of BCG instillation, infantile immunization, and the development of COVID-19 infection. Admission and/ or mortality because of COVID-19 was reported., Results: We could include data from 348 patients: including 188 and 160 patients from Ontario and British Columbia respectively. COVID-19 affected 15% of these patients. Intravesical BCG was used in 44% of these patients. Intravesical BCG and/or infantile BCG immunization did not correlate with the incidence of COVID-19 infection., Conclusions: Previous intravesical BCG and/ or a history of infantile BCG vaccination were not more/ less frequent in patients who had COVID-19 infection.

Objectives: We assessed the association of preexisting diabetes mellitus with all-cause mortality and organ support receipt in adult patients with sepsis., Design: Population-based cohort study., Setting: Ontario, Canada (2008-2019)., Population: Adult patients (18 yr old or older) with a first sepsis-related hospitalization episode., Interventions: None., Measurements and Main Results: The main exposure of interest was preexisting diabetes (either type 1 or 2). The primary outcome was all-cause mortality by 90 days; secondary outcomes included receipt of invasive mechanical ventilation and new renal replacement therapy. We report adjusted (for baseline characteristics using standardization) risk ratios (RRs) alongside 95% CIs. A main secondary analysis evaluated the potential mediation by prior metformin use of the association between preexisting diabetes and all-cause mortality following sepsis. Overall, 503,455 adults with a first sepsis-related hospitalization episode were included; 36% had preexisting diabetes. Mean age was 73 years, and 54% of the cohort were females. Preexisting diabetes was associated with a lower adjusted risk of all-cause mortality at 90 days (RR, 0.81; 95% CI, 0.80-0.82). Preexisting diabetes was associated with an increased risk of new renal replacement therapy (RR, 1.53; 95% CI, 1.46-1.60) but not invasive mechanical ventilation (RR, 1.03; 95% CI, 1.00-1.05). Overall, 21% (95% CI, 19-28) of the association between preexisting diabetes and reduced risk of all-cause mortality was mediated by prior metformin use., Conclusions: Preexisting diabetes is associated with a lower risk of all-cause mortality and higher risk of new renal replacement therapy among adult patients with sepsis. Future studies should evaluate the underlying mechanisms of these associations., Competing Interests: Dr. Scales holds operating grants from the Canadian Institute for Health Research. Dr. Lawler is supported by a Heart and Stroke Foundation of Canada National New Investigator Award. Dr. Shah is supported by the University of Toronto as the Novo Nordisk Research Chair in Equitable Care of Diabetes and Related Conditions. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)

We estimated COVID-19 transmission potential and case burden by variant type in Alberta, British Columbia, and Ontario, Canada, during January 23, 2020-January 27, 2022; we also estimated the effectiveness of public health interventions to reduce transmission. We estimated time-varying reproduction number (R t ) over 7-day sliding windows and nonoverlapping time-windows determined by timing of policy changes. We calculated incidence rate ratios (IRRs) for each variant and compared rates to determine differences in burden among provinces. R t corresponding with emergence of the Delta variant increased in all 3 provinces; British Columbia had the largest increase, 43.85% (95% credible interval [CrI] 40.71%-46.84%). Across the study period, IRR was highest for Omicron (8.74 [95% CrI 8.71-8.77]) and burden highest in Alberta (IRR 1.80 [95% CrI 1.79-1.81]). Initiating public health interventions was associated with lower R t and relaxing restrictions and emergence of new variants associated with increases in R t .

Rationale: Surgical lung biopsies are often required for the definitive diagnosis of nonmalignant pediatric diffuse lung diseases; however, the literature on mortality after surgical lung biopsy in pediatric patients is sparse. Objectives: To determine the 30-day postoperative mortality rate after surgical lung biopsies for nonmalignant lung disease in pediatric patients in Ontario, Canada, and to identify risk factors associated with mortality. Methods: We performed an observational cohort study using population-based health administrative data available from ICES in Ontario, Canada, from 2000 to 2019. Cases were identified using the Canadian Classification of Health Interventions. Inclusion criteria were first surgical lung biopsies between 2000 and 2019 and age <18 years. Individuals with lung cancer, lung transplant, or missing data were excluded. A multivariable logistic regression model with generalized estimating equation was used to estimate the 30-day odds of mortality after surgical lung biopsy and to identify patient characteristics associated with increased mortality while accounting for clustering by hospital. Results: We identified 1,474 pediatric patients who underwent surgical lung biopsy in Ontario between 2000 and 2019. The overall mortality rates decreased over the study duration from 6.6% (2000-2004) to 3.0% (2015-2019). The study cohort for multivariate analyses consisted of 1,342 patients who had complete data. The pediatric mortality 30 days after surgical lung biopsy was 5.1% but was <1% in elective cases. Risk factors for increased mortality included open surgical lung biopsy (vs. video-assisted) (odds ratio [OR], 13.13; 95% confidence interval [CI], 3.76, 45.87; P  < 0.001), nonelective procedure (OR, 11.74; 95% CI, 3.51, 39.27; P  < 0.001), younger age (<3 mo) (OR, 6.04; 95% CI, 2.40, 15.22; P  < 0.001), and higher comorbidity score (OR, 1.15; 95% CI, 1.05, 1.26; P   =  0.003). Conclusions: Pediatric mortality postsurgical lung biopsy is not insignificant, particularly in nonelective procedures. Other important risk factors to consider when pursuing pathologic diagnosis include surgical approach, younger age, and higher comorbidity.

The aim of this study was to describe the impact of marginalization on DLBCL overall survival (OS) within the Canadian setting. We conducted a population-based retrospective cohort study of adult patients with newly diagnosed DLBCL in Ontario between 1 January 2005 and 31 December 2017 receiving a rituximab-containing chemotherapy regimen with curative intent followed until 1 March 2020. Our primary exposure of interest was the Ontario Marginalization Index (ON-Marg). The primary outcome was 2-year OS, accounting for patient age, sex, cancer characteristics, comorbidity burden, and rural dwelling status. While two-year overall survival was inferior for individuals in the most deprived marginalization quintile (70.4% Q5 vs. 76.0% Q1), after adjustment for relevant covariates neither the composite ON-Marg nor any of its dimensions had a significant effect. Within the Canadian context, among patients who receive chemotherapy, marginalization may not have a significant association with overall survival when accounting for key patient covariates, lending support for preserved outcomes.

Astroviruses have been found in cattle and other species with encephalitis. Our objective was to determine the frequency of neurotropic bovine astrovirus (BoAstV) in cases of encephalitis in cattle ≥ 4-mo-old. Of 56 cases of idiopathic lymphocytic encephalitis examined retrospectively (1988-2019), fixed brain from 11 cases (19%) tested positive by semi-quantitative RT-PCR for BoAstV CH13/NeuroS1. None of the control cases tested positive, including 32 with other forms of encephalitis and 40 with no neurologic disease. Most astrovirus-positive cases were 1-2-y-old, with a range of 7 mo to 7 y, and affected both beef and dairy breeds with wide geographic distribution. BoAstV-positive cases had acute onset of neurologic signs of 12 h to 7 d before death or euthanasia. Affected cattle had lymphocytic inflammation throughout the brain including cerebrum, thalamus, midbrain, cerebellum, medulla oblongata, and spinal cord, and affecting gray and white matter. Further PCR testing identified a possible cause in 9 of the 45 (20%) remaining idiopathic cases of lymphocytic encephalitis, including eastern equine encephalitis virus, Listeria monocytogenes , bovine viral diarrhea virus, bovine alphaherpesvirus 1, and ovine gammaherpesvirus 2 (malignant catarrhal fever); we found no cases of infection by West Nile virus, rabies virus, or Chlamydia spp. No cause was identified in 36 of 56 (64%) cases of lymphocytic encephalitis. We frequently identified neurotropic BoAstV in cases of lymphocytic encephalitis that had no previously identified cause. Neurotropic BoAstV infections had gone undetected for decades, but the frequency of BoAstV infections has not increased among contemporary cases., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: Recent anecdotal reports suggest increasing numbers of people experiencing homelessness are visiting emergency departments (EDs) during cold weather seasons due to inadequate shelter availability. We examined monthly ED visits among patients experiencing homelessness to determine whether there has been a significant increase in such visits in 2022/2023 compared to prior years., Methods: We used linked health administrative data to identify cohorts experiencing homelessness in Ontario between October and March of the 2018/2019 to 2022/2023 years. We analyzed the monthly rate of non-urgent ED visits as a proxy measure of visits plausibly attributable to avoidance of cold exposure, examining rates among patients experiencing homelessness compared to housed patients. We excluded visits for overdose or COVID-19. We assessed level and significance of change in the 2022/2023 year as compared to previous cold weather seasons using Poisson regression., Results: We identified a total of 21,588 non-urgent ED visits across the observation period among patients experiencing homelessness in Ontario. Non-urgent ED visits increased 27% (RR 1.24 [95% CI 1.14-1.34]) in 2022/2023 compared to previous cold weather seasons. In Toronto, such visits increased by 70% (RR 1.68 [95% CI 1.57-1.80]). Among housed patients, non-urgent ED visits did not change significantly during this time period., Conclusion: Rates of ED visits plausibly attributable to avoidance of cold exposure by individuals experiencing homelessness increased significantly in Ontario in 2022/2023, most notably in Toronto. This increase in ED visits may be related to inadequate access to emergency shelter beds and warming services in the community., (© 2024. The Author(s), under exclusive licence to Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

Objectives: The addition of bevacizumab to chemotherapy for platinum-resistant (PL-R) ovarian cancer (OC) improved progression-free (PFS) but not overall survival (OS) in clinical trials. We explored real-world outcomes in Ontario, Canada, and compared survival in the pre- and post-bevacizumab era., Methods: Administrative databases were utilized to identify all patients treated with bevacizumab for PL-R OC. Time on treatment (ToT) was used as surrogate for PFS. Median OS was determined using the Kaplan-Meier method. Factors associated with ToT/OS were identified using a Cox proportional hazard model. A before and after comparative effectiveness analysis was performed to determine mOS for patients treated pre- and post-bevacizumab approval., Results: From 2017 to 2019, 176 patients received bevacizumab. Median ToT was 3 months and OS was 11 months. Sixty-four percent received liposomal doxorubicin and 34% received paclitaxel. ToT (6 vs 3 months; HR 0.44; p < 0.0001) and OS (14 vs 9 months; HR 0.45; p = 0.0089) were longer with bevacizumab/paclitaxel. OS was not significantly different pre- and post-bevacizumab funding (8 vs 9 months; HR 1.01; 0.937). Median OS increased for those receiving paclitaxel (6 vs 11 months), but those in the post group were younger, more likely to have undergone primary surgery and had less co-morbidities., Conclusion: Real-world outcomes with bevacizumab in PL-R OC are inferior to those in the pivotal clinical trial. Survival has not significantly improved since funding became publicly available, indicating a substantial efficacy-effectiveness gap between trial and real-world outcomes. Median OS and ToT were significantly better when bevacizumab was given with paclitaxel., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

In a population-based cohort of postpartum individuals in Ontario, Canada, this study aimed to determine the risk of non-fatal self-harm and suicide within one year of an initial postpartum psychiatric emergency department (ED) visit (2008-2020), and the key associated factors. Of 16,475 postpartum individuals with psychiatric ED visits, 714 (4.3 %) had non-fatal self-harm within one year, and 23 (0.15 %) died by suicide. Risk was substantially higher for those with self-harm at the initial presentation. Further efforts to connect individuals with postpartum psychiatric ED visits with needed inpatient care and outpatient follow-up are required to reduce non-fatal self-harm and suicide risk., Competing Interests: Declaration of competing interest SNV reports royalties from UpToDate for authorship of materials related to antidepressants and pregnancy. LCB, KF, JZ, HKB, SEB, and PK have no interests to declare., (Copyright © 2024. Published by Elsevier B.V.)

The seroprevalence and risk factors for exposure to Neospora caninum and Neospora hughesi in broodmares in Ontario were investigated. Sixty of the 219 (27.4%) study broodmares were seropositive for N. caninum and 65/219 (29.7%) for N. hughesi with cut-offs of ≥1:40 and ≥1:160, respectively. Thirty-one of 63 participating farms (49.2%) had at least 1 broodmare seropositive for N. caninum. Thirty-three of the 63 (52.4%) participating farms had at least 1 broodmare positive for N. hughesi. Risk factors for N. caninum included presence of farm dogs (OR = 6.70; 95% CI = 2.14-20.97; p = 0.001), and high stocking density (OR = 2.83; 95% CI = 1.27-6.30; p = 0.011). Presence of livestock, excluding cattle, was associated with reduced risk of exposure (OR = 0.17; 95% CI = 0.06-0.53; p = 0.002). The only risk factor for exposure to N. hughesi was feeding hay on the ground in the paddock (OR = 4.31; 95% CI = 1.65-11.22; p = 0.003). This study demonstrated widespread exposure to Neospora spp. in broodmares in Ontario., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Objectives: Echocardiography is an essential diagnostic modality known to have wide regional utilization variations. This study's objectives were to quantify regional variations and to examine the extent to which they are explained by differences in population age, sex, cardiac disease prevalence (CDP), and social determinants of health (SDH) risk., Methods: This is an observational study of all echocardiography exams performed in Ontario in 2019/20 (n = 695,622). We measured regional variations in echocardiography crude rates and progressively standardized rates for population age, sex, CDP, and SDH risk., Results: After controlling for differences in population age, sex, and CDP, Ontario's highest rate regions had echocardiography rates 57% higher than its lowest rate regions. Forty eight percent of total variation was not explained by differences in age, sex, and CDP. CDP increased with SDH risk. Access to most cardiac diagnostics was negatively correlated with SDH risk, while cardiac catheterization rates were positively correlated with SDH risk., Conclusion: Variations analysis that adjusts for age and sex only without including clinical measures of need are likely to overestimate the unwarranted portion of total variation. Substantial variations persisted despite a mandatory provider accreditation policy aimed at curtailing them. The associations between variations and SDH risks imply a need to redress access and outcome inequities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background and Objectives: While immigrants to high-income countries have a lower risk of multiple sclerosis (MS) compared with host populations, it is unknown whether this lower risk among immigrants increases over time. Our objective was to evaluate the association between proportion of life spent in Canada and the hazard of incident MS in Canadian immigrants., Methods: We conducted a population-based retrospective cohort study in Ontario, using linked health administrative databases. We followed immigrants, who arrived in Ontario between 1985 and 2003, from January 1, 2003, to December 31, 2016, to record incident MS using a validated algorithm based on hospital admission or outpatient visits. We derived proportion of life spent in Canada based on age at arrival and time since immigration obtained from linked immigration records. We used multivariable proportional hazard models, adjusting for demographics and comorbidities, to evaluate the association between proportion of life in Canada and the incidence of MS, where proportion of life was modelled using restricted cubic spline terms. We further evaluated the role of age at migration (15 or younger vs older than 15 years), sex, and immigration class in sensitivity analyses., Results: We included 1.5 million immigrants (49.9% female, mean age 35.9 [SD 14.2] years) who had spent a median of 20% (Q1-Q3 10%-30%) of their life in Canada. During a mean follow-up of 13.9 years (SD 1.0), 934 (0.44/100,000 person-years) were diagnosed with MS. Compared with the median, a higher risk of MS was observed at higher values of proportion of life spent (e.g., hazard ratio [70% vs 20% proportion of life] 1.38; 1.07-1.78). This association did not vary by sex ( p (sex × proportion of life) = 0.70) or immigration class ( p (immigration class × proportion of life) = 0.13). The results did not vary by age at migration but were statistically significant only at higher values of proportion of life for immigrants aged 15 years or younger at arrival., Discussion: The risk of incident MS in immigrants varied with the proportion of life spent in Canada, suggesting an acculturation effect on MS risk. Further work is required to understand environmental and sociocultural factors driving the observed association.

Objectives: Emergency departments (EDs) are a vital part of healthcare systems, at times acting as a gateway to community-based mental health (MH) services. This may be particularly true for veterans of the Royal Canadian Mounted Police who were released prior to 2013 and the Canadian Armed Forces, as these individuals transition from federal to provincial healthcare coverage on release and may use EDs because of delays in obtaining a primary care provider. We aimed to estimate the hazard ratio (HR) of MH-related ED visits between veterans and non-veterans residing in Ontario, Canada: (1) overall; and by (2) sex; and (3) length of service., Methods: This retrospective cohort study used administrative healthcare data from 18,837 veterans and 75,348 age-, sex-, geography-, and income-matched non-veterans residing in Ontario, Canada between April 1, 2002, and March 31, 2020. Anderson-Gill regression models were used to estimate the HR of recurrent MH-related ED visits during the period of follow-up. Sex and length of service were used as stratification variables in the models., Results: Veterans had a higher adjusted HR (aHR) of MH-related ED visits than non-veterans (aHR, 1.97, 95% CI, 1.70 to 2.29). A stronger effect was observed among females (aHR, 3.29; 95% CI, 1.96 to 5.53) than males (aHR, 1.78; 95% CI, 1.57 to 2.01). Veterans who served for 5-9 years had a higher rate of use than non-veterans (aHR, 3.76; 95% CI, 2.34 to 6.02) while veterans who served for 30+ years had a lower rate compared to non-veterans (aHR, 0.60; 95% CI, 0.42 à 0.84)., Conclusions: Rates of MH-related ED visits are higher among veterans overall compared to members of the Ontario general population, but usage is influenced by sex and length of service. These findings indicate that certain subpopulations of veterans, including females and those with fewer years of service, may have greater acute mental healthcare needs and/or reduced access to primary mental healthcare., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: The risk of incident dementia after surgery in older adults is unclear. The study objective was to examine the rate of incident dementia among older adults after elective surgery compared with a matched nonsurgical control group., Methods: We conducted a population-based, propensity-matched retrospective cohort study using data from linked administrative databases in Ontario, Canada. All community-dwelling individuals aged 66 years and older who underwent one of five major elective surgeries between April 1, 2007 and March 31, 2011 were included. Each surgical patient was matched 1:1 on surgical specialty of the surgeon at consultation, age, sex, fiscal year of entry, and propensity score with a patient who attended an outpatient visit with a surgeon of the same surgical specialty but did not undergo surgery. Patients were followed for up to 5 years after cohort entry for the occurrence of a new dementia diagnosis, defined from administrative data. Cause-specific hazard models were used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for the association between surgery and the hazard of incident dementia. Subgroup and sensitivity analyses were performed., Results: A total of 27,878 individuals (13,939 matched pairs) were included in the analysis. A total of 640 (4.6%) individuals in the surgical group and 965 (6.9%) individuals in the control group developed dementia over the 5-year follow-up period. Individuals who underwent surgery had a reduced rate of incident dementia compared with their matched nonsurgical controls (HR 0.88; 95% CI 0.80-0.97; p = 0.01). This association was persistent in most subgroups and after sensitivity analyses., Conclusions: Elective surgery did not increase the rate of incident dementia when compared with matched nonsurgical controls. This could be an important consideration for patients and surgeons when elective surgery is considered., (© 2024 The Authors. Journal of the American Geriatrics Society published by Wiley Periodicals LLC on behalf of The American Geriatrics Society.)

Background: Before the COVID-19 pandemic, access to prenatal care was lower among some socio-demographic groups. This pandemic caused disruptions to routine preventative care, which could have increased inequalities., Objectives: To investigate if the COVID-19 pandemic increased inequalities in access to prenatal care among those who are younger, live in rural areas, have a lower socio-economic situation (SES) and are recent immigrants., Methods: We used linked administrative datasets from ICES to identify a population-based cohort of 455,245 deliveries in Ontario from January 2018 to December 2021. Our outcomes were first-trimester prenatal visits, first-trimester ultrasound and adequacy of prenatal care. We used joinpoint analysis to examine outcome time trends and identify trend change points. We stratified analyses by age, rural residence, SES and recent immigration, and examined risk differences (RD) with 95% confidence intervals (CI) between groups at the beginning and end of the study period., Results: For all outcomes, we noted disruptions to care beginning in March or April 2020 and returning to previous trends by November 2020. Inequalities were stable across groups, except recent immigrants. In July 2017, 65.0% and 69.8% of recent immigrants and non-immigrants, respectively, received ultrasounds in the first trimester (RD -4.8%, 95% CI -8.0, -1.5). By October 2020, this had increased to 75.4%, with no difference with non-immigrants (RD 0.4%, 95% CI -2.4, 3.2). Adequacy of prenatal care showed more intensive care as of November 2020, reflecting a higher number of visits., Conclusions: We found no evidence that inequalities between socio-economic groups that existed prior to the pandemic worsened after March 2020. The pandemic may be associated with increased access to care for recent immigrants. The introduction of virtual visits may have resulted in a higher number of prenatal care visits., (© 2024 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd.)

Background: Across Canada, the COVID-19 pandemic occurred amidst an ongoing drug toxicity crisis. Although elevated rates of substance-related harms have been observed nationally, it remains unknown if the pandemic state of emergency led to disproportionate increases in opioid toxicities among people with opioid use disorder (OUD) compared to those without., Methods: We conducted a population-based repeated cross-sectional time series analysis of fatal and non-fatal opioid toxicities between January 1, 2014, and December 31, 2021, in Ontario, Canada. We used interventional autoregressive integrated moving average models to examine the impact of the pandemic on monthly rates of opioid toxicities per 100,000 Ontario residents stratified by people with and without OUD., Results: We identified 80,296 opioid toxicities of which 53.5 % occurred among people with OUD. Among 52,052 unique individuals, 60.5 % were male and 46.2 % were 25-44 years old. Between January 2014 and December 2021, the rate of opioid toxicities increased from 2.6 to 10.5 per 100,000 (rate ratio [RR]=4.07). The magnitude of this increase differed among people with OUD (0.8 to 7.4 per 100,000; RR=9.35) and without OUD (1.8 to 3.1 per 100,000; RR=1.74). We observed a significant ramp increase in the overall rate of opioid toxicities following the declaration of the pandemic emergency in March 2020 (+0.19 per 100,000 monthly, 95 % CI: 0.029, 0.36, p = 0.021). In a stratified analysis, we found a similar ramp increase among people with OUD (+0.19 per 100,000 monthly, 95 % CI: 0.10, 0.28, p < 0.001); however, this was not observed among people without OUD (p = 0.95)., Conclusions: The rate of opioid toxicities accelerated across Ontario following the pandemic-related state of emergency, with the majority of this increase among people with OUD. The important differences observed among people with OUD compared with those without, highlights the critical need for improved access to harm reduction and treatment interventions among this population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objective: To estimate prevalence and incidence rates over time in children and youth with attention deficit/hyperactivity disorder from the validation of population-based administrative data algorithms using family physicians' electronic medical records as a reference standard., Methods: A retrospective cohort study was conducted in Ontario, Canada to identify attention deficit/hyperactivity disorder among children and youth aged 1-24 years in health administrative data derived from case-finding algorithms using family physicians' electronic medical records. Multiple administrative data algorithms identifying attention deficit/hyperactivity disorder cases were developed and tested from physician-diagnosis of attention deficit/hyperactivity disorder in the electronic medical record to determine their diagnostic accuracy. We calculated algorithm performance using sensitivity, specificity, and predictive values. The most optimal algorithm was used to estimate prevalence and incidence rates of attention deficit/hyperactivity disorder from 2014 to 2021 in Ontario., Results: The optimal performing algorithm was "2 physician visits for attention deficit/hyperactivity disorder in 1 year or 1 attention deficit/hyperactivity disorder-specific prescription" with sensitivity: 83.2% (95% confidence interval [CI], 81.8% to 84.5%), specificity: 98.6% (95% CI, 98.5% to 98.7%), positive predictive value: 78.6% (95% CI, 77.1% to 80.0%) and negative predictive value: 98.9% (95% CI, 98.8% to 99.0%). From 2014, prevalence rates for attention deficit/hyperactivity disorder increased from 5.29 to 7.48 per 100 population in 2021 ( N  = 281,785). Males had higher prevalence rates (7.49 to 9.59 per 100 population, 1.3-fold increase) than females (2.96-5.26 per 100 population, 1.8-fold increase) from 2014 to 2021. Incidence rates increased from 2014 (0.53 per 100 population) until 2018, decreased in 2020 then rose steeply in 2021 (0.89 per 100 population, N  = 34,013). Males also had higher incidence rates than females from 2014 to 2020 with females surpassing males in 2021 (0.70-0.81 per 100 male population,1.2-fold increase versus 0.36-0.97 per 100 female population, 2.7-fold increase)., Conclusions: Attention deficit/hyperactivity disorder is increasing in prevalence. We developed an administrative data algorithm that can reliably identify children and youth with attention deficit/hyperactivity disorder with good diagnostic accuracy., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.