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Background Learning health systems have been gaining traction over the past decade. The purpose of this study was to understand the spread of learning health systems in primary care, including where they have been implemented, how they are operating, and potential challenges and solutions. Methods We completed a scoping review by systematically searching OVID Medline®, Embase®, IEEE Xplore®, and reviewing specific journals from 2007 to 2020. We also completed a Google search to identify gray literature. Results We reviewed 1924 articles through our database search and 51 articles from other sources, from which we identified 21 unique learning health systems based on 62 data sources. Only one of these learning health systems was implemented exclusively in a primary care setting, where all others were integrated health systems or networks that also included other care settings. Eighteen of the 21 were in the United States. Examples of how these learning health systems were being used included real-time clinical surveillance, quality improvement initiatives, pragmatic trials at the point of care, and decision support. Many challenges and potential solutions were identified regarding data, sustainability, promoting a learning culture, prioritization processes, involvement of community, and balancing quality improvement versus research. Conclusions We identified 21 learning health systems, which all appear at an early stage of development, and only one was primary care only. We summarized and provided examples of integrated health systems and data networks that can be considered early models in the growing global movement to advance learning health systems in primary care.

A learning health system model can be used to efficiently evaluate and incorporate evidence-based care into practice. However, there is a paucity of evidence describing key organizational attributes needed to ensure a successful learning health system within primary care. We interviewed stakeholders for a primary care learning health system in Ontario, Canada (the Alliance for Healthier Communities) to identify strengths and areas for improvement.We conducted a qualitative descriptive study using individual semistructured interviews with Alliance stakeholders between December 2019 and March 2020. The Alliance delivers community-governed primary healthcare through 109 organizations including Community Health Centres (CHCs). All CHC staff within the Alliance were invited to participate. Interviews were audio-recorded and transcribed verbatim. We performed a thematic analysis using a team approach.We interviewed 29 participants across six CHCs, including Executive Directors, managers, healthcare providers and data support staff. We observed three foundational elements necessary for a successful learning health system within primary care: shared organizational goals and culture, data quality and resources. Building on this foundation, people are needed to drive the learning health system, and this is conditional on their level of engagement. The main factors motivating staff member's engagement with the learning health system included their drive to help improve patient care, focusing on initiatives of personal interest and understanding the purpose of different initiatives. Areas for improvement were identified such as the ability to extract and use data to inform changes in real-time, better engagement and protected time for providers to do improvement work, and more staff dedicated to data extraction and analysis.We identified key components needed to establish a learning health system in primary care. Similar primary care organizations in Canada and elsewhere can use these insights to guide their development as learning health systems.

Purpose Severe acute kidney injury (AKI) is associated with a significant risk of mortality and persistent renal replacement therapy (RRT) dependence. The objective of this study was to develop prediction models for mortality at 90-day and 1-year following RRT initiation in critically ill patients with AKI. Methods All patients who commenced RRT in the intensive care unit for AKI at a tertiary care hospital between 2007 and 2014 constituted the development cohort. We evaluated the external validity of our mortality models using data from the multicentre OPTIMAL-AKI study. Results The development cohort consisted of 594 patients, of whom 320(54%) died and 40 (15% of surviving patients) remained RRT-dependent at 90-day Eleven variables were included in the model to predict 90-day mortality (AUC:0.79, 95%CI:0.76–0.82). The performance of the 90-day mortality model declined upon validation in the OPTIMAL-AKI cohort (AUC:0.61, 95%CI:0.54–0.69) and showed modest calibration. Similar results were obtained for mortality model at 1-year. Conclusions Routinely collected variables at the time of RRT initiation have limited ability to predict mortality in critically ill patients with AKI who commence RRT.

Rationale & Objective Surveillance blood work is routinely performed in maintenance hemodialysis (HD) recipients. Although more frequent blood testing may confer better outcomes, there is little evidence to support any particular monitoring interval. Study Design Retrospective population-based cohort study. Setting & Participants All prevalent HD recipients in Ontario, Canada, as of April 1, 2011, and a cohort of incident patients commencing maintenance HD in Ontario, Canada, between April 1, 2011, and March 31, 2016. Exposure Frequency of surveillance blood work, monthly versus every 6 weeks. Outcomes The primary outcome was all-cause mortality. Secondary outcomes were major adverse cardiovascular events, all-cause hospitalization, and episodes of hyperkalemia. Analytical Approach Cox proportional hazards with adjustment for demographic and clinical characteristics was used to evaluate the association between blood testing frequency and all-cause mortality. Secondary outcomes were evaluated using the Andersen-Gill extension of the Cox model to allow for potential recurrent events. Results 7,454 prevalent patients received care at 17 HD programs with monthly blood sampling protocols (n=5,335 patients) and at 8 programs with blood sampling every 6 weeks (n=2,119 patients). More frequent monitoring was not associated with a lower risk for all-cause mortality compared to blood sampling every 6 weeks (adjusted HR, 1.16; 95% CI, 0.99-1.38). Monthly monitoring was not associated with a lower risk for any of the secondary outcomes. Results were consistent among incident HD recipients. Limitations Unmeasured confounding; limited data for center practices unrelated to blood sampling frequency; no information on frequency of unscheduled blood work performed outside the prescribed sampling interval. Conclusions Monthly routine blood testing in HD recipients was not associated with a lower risk for death, cardiovascular events, or hospitalizations as compared with testing every 6 weeks. Given the health resource implications, the frequency of routine blood sampling in HD recipients deserves careful reassessment.

Background The ability to identify patients with autosomal dominant polycystic kidney disease (ADPKD) and distinguish them from patients with similar conditions in healthcare administrative databases is uncertain. We aimed to measure the sensitivity and specificity of different ADPKD administrative coding algorithms in a clinic population with non-ADPKD and ADPKD kidney cystic disease. Methods We used a dataset of all patients who attended a hereditary kidney disease clinic in Toronto, Ontario, Canada between 1 January 2010 and 23 December 2014. This dataset included patients who met our reference standard definition of ADPKD or other cystic kidney disease. We linked this dataset to healthcare databases in Ontario. We developed eight algorithms to identify ADPKD using the International Classification of Diseases, 10th Revision (ICD-10) codes and provincial diagnostic billing codes. A patient was considered algorithm positive if any one of the codes in the algorithm appeared at least once between 1 April 2002 and 31 March 2015. Results The ICD-10 coding algorithm had a sensitivity of 33.7% [95% confidence interval (CI) 30.0–37.7] and a specificity of 86.2% (95% CI 75.7–92.5) for the identification of ADPKD. The provincial diagnostic billing code had a sensitivity of 91.1% (95% CI 88.5–93.1) and a specificity of 10.8% (95% CI 5.3–20.6). Conclusions ICD-10 coding may be useful to identify patients with a high chance of having ADPKD but fail to identify many patients with ADPKD. Provincial diagnosis billing codes identified most patients with ADPKD and also with other types of cystic kidney disease.

Acute kidney injury (AKI) is common among hospitalized children and is associated with increased hospital length of stay and costs. However, there are limited data on postdischarge health care utilization after AKI hospitalization. Our objectives were to evaluate health care utilization and physician follow-up patterns after dialysis-treated AKI in a pediatric population.Retrospective cohort study, using provincial health administrative databases.All children (0-18 years) hospitalized between 1996 and 2017 in Ontario, Canada. Excluded individuals comprised non-Ontario residents; those with metabolic disorders or poisoning; and those who received dialysis or kidney transplant before admission, a kidney transplant by 104 days after discharge, or were receiving dialysis 76-104 days from dialysis start date.Episodes of dialysis-treated AKI, identified using validated health administrative codes. AKI survivors were matched to 4 hospitalized controls without dialysis-treated AKI by age, sex, and admission year.Our primary outcome was postdischarge hospitalizations, emergency department visits, and outpatient physician visits. Secondary outcomes included outpatient visits by physician type and composite health care costs.Proportions with≥1 event and rates (per 1,000 person-years). Total and median composite health care costs. Adjusted rate ratios using negative binomial regression models.We included 1,688 pediatric dialysis-treated AKI survivors and 6,752 matched controls. Dialysis-treated AKI survivors had higher rehospitalization and emergency department visit rates during the analyzed follow-up periods (0-1, 0-5, and 0-10 years postdischarge, and throughout follow-up), and higher outpatient visit rates in the 0-1-year follow-up period. The overall adjusted rate ratio for rehospitalization was 1.46 (95% CI, 1.25-1.69; P0.0001) and for outpatient visits was 1.16 (95% CI, 1.09-1.23; P=0.01). Dialysis-treated AKI survivors also had higher health care costs. Nephrologist follow-up was infrequent among dialysis-treated AKI survivors (18.6% by 1 year postdischarge).Potential miscoding of study exposures or outcomes. Residual uncontrolled confounding. Data for health care costs and emergency department visits was unavailable before 2006 and 2001, respectively.Dialysis-treated AKI survivors had greater postdischarge health care utilization and costs versus hospitalized controls. Strategies are needed to improve follow-up care for children after dialysis-treated AKI to prevent long-term complications.

Background Chronic pain is common, and its management is complex in patients with chronic kidney disease (CKD), but limited data are available on opioid prescribing. We examined opioid prescribing for non-cancer and non-end-of-life care in patients with CKD. Methods This was a population-based retrospective cohort study using administrative databases in Ontario, Canada which included adults with CKD defined by an estimated glomerular filtration rate (eGFR) Results We included 680 445 adults with CKD, and 198 063 (29.1%) were prescribed opioids. Codeine (14.9%) and hydromorphone (7.2%) were the most common opioids. Among opioid users, 24.3% had repeated or long-term use, 26.1% were prescribed high doses and 56.8% were new users. Opioid users were more likely to be female, had cardiac disease or a mental health diagnosis, and had more healthcare visits. The proportions for potentially inappropriate prescribing indicators varied (e.g. 50.1% with eGFR Conclusions Opioid use was common in patients with CKD. While opioid prescriptions and potentially inappropriate prescribing have declined in recent years, interventions to improve pain management without the use of opioids and education on safer prescribing practices are needed.

BACKGROUND: In 2007, an electronic repository called the Ontario Laboratories Information System (OLIS) was introduced to allow health care providers timely access to laboratory test results. Since not all laboratories began submitting their data to OLIS simultaneously, we sought to create a date-dependent table of geographic regions (forward sortation areas [FSAs]) from which people would likely present to a hospital linked to OLIS. METHODS: In this descriptive study, we used administrative data to capture adults in Ontario who presented to the emergency department for any reason from 2007 to 2017. To assess changes over time, we classified all emergency department visits into fiscal quarters. The primary outcome measure was the proportion of people in a given FSA presenting to an emergency department at an OLIS-linked hospital (v. a hospital not linked to OLIS). To be included in the catchment area, at least 90% of all emergency department visits in a given quarter from a given FSA must have occurred at an OLIS-linked hospital. RESULTS: By Dec. 31, 2017, 323 (61.4%) of 526 Ontario FSAs were in the catchment area (a population of about 8.5 million). There were no differences in selected demographic characteristics or comorbidities between people residing within the catchment area of OLIS-linked hospitals and those residing in the catchment area of unlinked hospitals on Dec. 31, 2017. We used the FSA information to construct a date-dependent table of geographic areas likely to have hospital laboratory data available in OLIS for future studies. INTERPRETATION: We identified relevant Ontario geographic regions from which people would likely present to a hospital linked to OLIS. These geographic regions constitute a catchment area that may be used in future studies to capture adults who present to an OLIS-linked hospital with laboratory-defined conditions such as acute kidney injury, hyperkalemia and hyponatremia.

BACKGROUND: End-stage kidney disease is a serious complication of diabetes. We describe the prevalence of chronic kidney disease, prevalence and incidence of end-stage kidney disease and quality of care of early-stage chronic kidney disease for First Nations people with diabetes compared to other Ontarians with diabetes. METHODS: We conducted a retrospective cohort study in Ontario using linked administrative data at ICES. We included adults with incident diabetes between 1994 and 2014, and used laboratory values to identify kidney disease and quality indicators for care for early-stage disease. We compared measures in First Nations people to those in other people in Ontario, and used direct age and sex standardization. We used Cox proportional hazards regression to compare the incidence of end-stage kidney disease between groups. RESULTS: Our study included 21 968 First Nations people with diabetes. The age- and sex-standardized prevalence of chronic kidney disease was higher for First Nations people than for other Ontarians (20.7% v. 18.4%), as was the prevalence of end-stage kidney disease (2.9% v. 1.0%). The incidence of end-stage kidney disease was higher among First Nations people than among other people in Ontario (9.3 v. 4.7 events per 10 000 person-years; age- and sex-adjusted hazard ratio 2.23, 95% confidence interval 1.72–2.89). The 2 groups were similarly likely to receive recommended medications, but First Nations people were less likely to receive laboratory tests for their kidney disease. INTERPRETATION: Despite receiving similar quality of care for early-stage kidney disease, First Nations people with diabetes had higher rates of end-stage kidney disease than other Ontarians. Further research is needed to better understand contributing factors to help inform future interventions.

Background and objectives There is a limited appreciation of the epidemiology of dialysis-receiving AKI in children. The primary objective of the study was to evaluate changes in the incidence of dialysis-receiving AKI among children over a period of 20 years in Ontario, Canada. The secondary objectives were to assess temporal trends in the utilization of various dialysis modalities and 30-day mortality among children with dialysis-receiving AKI. Design, setting, participants, & measurements All children (29 days to 18 years) who received their first dialysis for AKI between 1996 and 2015 were identified from healthcare administrative databases. Those who received dialysis for ESKD, inborn errors of metabolism, and poisonings were excluded. The incidence rates of dialysis-receiving AKI were reported annually. The Cochran—Armitage test was used to assess trends in the incidence and short-term mortality after dialysis-receiving AKI. Results We identified 1394 children treated with dialysis for AKI during a hospital stay. There was a significant increase in the incidence of dialysis-receiving AKI among hospitalized children from 1996 (0.58 per 1000 person-years) to 2015 (0.65 per 1000 person-years) (P=0.01). The use of continuous kidney replacement therapy and intermittent hemodialysis increased whereas the relative use of peritoneal dialysis declined over time. Thirty-day mortality rates after dialysis-receiving AKI increased from 14% to 25% between 1996 and 2009 and reduced to 19% in the more recent years (P=0.03). Conclusions In Ontario, the incidence of dialysis-receiving AKI among children has increased between 1996 and 2015. The use of peritoneal dialysis for AKI has declined and the short-term mortality after dialysis-receiving AKI has increased.

Purpose To determine whether patients with severe acute kidney injury who receive dialysis (AKI-D) experience better outcomes at centres that care for more patients with AKI-D. Materials and methods Linked administrative datasets where used to perform a retrospective cohort study of all critically ill patients in Ontario, Canada, who had a first episode of AKI-D between 2002 and 2011. Centre volume for a given year, was designated by calculating the mean number of patients treated with acute dialysis at that centre during that year and the one preceding it. Patients treated at that centre were then assigned to a centre volume quartile for that year. Results We identified 19,658 critically ill patients with AKI-D treated at 54 Ontario hospitals. Mortality and dialysis dependence at 90-days were 46% and 31%, respectively. Centre volume was not associated with mortality at 90 days (with quartile 1 as the reference, adjusted odds ratio (aOR) 1.16 (95% CI, 0.87 - 1.54) in quartile 2, aOR 1.17 (95% CI, 0.91 - 1.50) in quartile 3, and aOR 1.06 (95% CI, 0.81 - 1.41) in quartile 4). Conclusions There are no Centre volume survival associations in the management of AKI-D despite high mortality and dependence rate.

There is a perception that patients with autosomal dominant polycystic kidney disease (ADPKD) are more likely to develop kidney stones than the general population.To compare the rate of hospital encounter with kidney stones and the rate of stone interventions between patients with and without ADPKD.Retrospective cohort study.Ontario, Canada.Patients with and without ADPKD who had a prior hospital encounter between 2002 and 2016.Rate of hospital encounter with kidney stones and rate of stone intervention.We used inverse probability exposure weighting based on propensity scores to balance baseline indicators of health between patients with and without ADPKD. We followed each patient until death, emigration, outcomes, or March 31, 2017. We used a Cox proportional hazards model to compare event rates between the two groups.Patients with ADPKD were at higher risk of hospital encounter with stones compared with patients without ADPKD (81 patients of 2094 with ADPKD [3.8%] vs 60 patients of 1902 without ADPKD [3.2%]; 8.9 vs 5.1 events per 1000 person-years; hazard ratio 1.6 [95% CI, 1.3-2.1]). ADPKD was not associated with a higher risk of stone intervention (49 of 2094 [2.3%] vs 47 of 1902 [2.4%]; 5.3 vs 3.9 events per 1000 person-years; hazard ratio 1.2 [95% CI = 0.9-1.3]).We did not have information on kidney stone events outside of the hospital. There is a possibility of residual confounding.ADPKD was a significant risk factor for hospital encounters with kidney stones.Il existe une perception selon laquelle les patients atteints de polykystose rénale autosomique dominante (ADPKD) seraient plus susceptibles de développer des calculs rénaux que la population générale.Comparer les taux d’hospitalisations et d’interventions pour calculs rénaux entre des patients atteints ou non d’ADPKD.Étude de cohorte rétrospective.Ontario, Canada.Des patients atteints ou non d’ADPKD qui avaient déjà été hospitalisés entre 2002 et 2016.Les taux d’hospitalisations et d’interventions pour calculs rénaux.Nous avons utilisé une pondération d’exposition à probabilité inverse fondée sur les scores de propension afin d’équilibrer les indicateurs de santé de base entre les patients atteints ou non d’ADPKD. Nous avons suivi chaque patient jusqu’à son décès, jusqu’à son émigration, jusqu’au résultat ou jusqu’au 31 mars 2017. Nous avons utilisé un modèle de risques proportionnels de Cox pour comparer les taux d’événements entre les deux groupes.Les patients atteints d’ADPKD présentaient un risque plus élevé d’être hospitalisés pour calculs rénaux que les patients non atteints d’ADPKD (81 patients sur 2094 atteints d’ADPKD [3,8 %] contre 60 patients sur 1902 sans ADPKD [3,2 %]; 8,9 contre 5,1 événements pour 1 000 années-personnes; risque relatif: 1,6 [IC 95 %: 1,3 à 2,1]). L’ADPKD n’a pas été associée à un risque plus élevé d’interventions pour retirer des calculs rénaux (49 patients sur 2094 atteints d’ADPKD [2,3 %] contre 47 patients sur 1902 sans ADPKD [2,4 %]; 5,3 contre 3,9 événements pour 1 000 années-personnes; risque relatif: 1,2 [IC 95 %: 0,9 à 1,3]).Nous n’avions pas d’information sur les événements liés aux calculs rénaux à l’extérieur de l’hôpital. Il existe une possibilité de facteurs de confusion résiduels.L’ADPKD s’est avéré un facteur de risque important d’être hospitalisé pour des calculs rénaux.

Background Patients with diabetes receiving chronic, in-center hemodialysis face healthcare challenges. We examined the prevalence of gaps in their diabetes care, explored regional differences, and determined predictors of care gaps. Methods We conducted a population-based, retrospective study between January 1, 2016 and January 1, 2018 in Ontario, Canada. We included adults with prevalent diabetes mellitus receiving in-center hemodialysis as of January 1, 2018 and examined the proportion with (1) insufficient or excessive glycemic monitoring, (2) suboptimal screening for diabetes-related complications (retinopathy and cardiovascular screening), (3) hospital encounters for hypo- or hyperglycemia, and (4) hospital encounters for hypertension in the 2 years prior (January 1, 2016 to January 1, 2018). We then identified patient, provider, and health-system factors associated with more than one care gap and used multivariable logistic regression to determine predictors. Further, we used geographic information systems to explore spatial variation in gaps. Results There were 4173 patients with diabetes receiving in-center hemodialysis; the mean age was 67 years, 39% were women, and the majority were of lower socioeconomic status. Approximately 42% of patients had more than one diabetes care gap, the most common being suboptimal retinopathy screening (53%). Significant predictors of more than one gap included younger age, female sex, shorter duration of diabetes, dementia, fewer specialist visits, and not seeing a physician for diabetes. There was evidence of spatial variation in care gaps across our region. Conclusions There are opportunities to improve diabetes care in patients receiving in-center hemodialysis, particularly screening for retinopathy. Focused efforts to bring diabetes support to high-risk individuals might improve their care and outcomes.

Ureteroscopy is a minimally invasive treatment option for upper tract stones. The distorted kidney anatomy in patients with autosomal dominant polycystic kidney disease (ADPKD) may place them at higher risk for ureteroscopic complications.To compare the 30-day risk of ureteroscopic complications between patients with and without ADPKD.Retrospective cohort study.Ontario, Canada.Seventy three patients with ADPKD and 81 445 patients without ADPKD who underwent ureteroscopy for upper urinary tract stones between April 1, 2002, and March 1, 2018.A 30-day risk of (1) hospital presentation with ureteroscopic complications (which was a composite outcome of either emergency department visit or hospital admission with acute kidney injury, urinary tract infection, or sepsis); (2) all-cause hospital presentation; (3) all-cause hospital admission; and (4) all-cause emergency department visit.We regressed outcomes on demographic variables, health care use in the prior 1-year, various procedures and comorbidities related to the outcome in the prior 5 years, and prescribed medications filled in the past 120 days using modified Poisson regression to compare the risk ratio (RR) of each outcome between patients with and without ADPKD.The median (interquartile, IQR) age was 44 (38-60 years) in the ADPKD group and 53 (42-64) in the control group. About 40% were women in both groups. The risk of ureteroscopic complications was not significantly different in patients with versus without ADPKD (8.2% vs 4.3%; adjusted RR = 1.5, 95% confidence interval [CI] = 0.7-3.2). Patients with versus without ADPKD were more likely to present to hospital after their procedure (35.6% vs. 20.0%; adjusted RR = 1.6, 95% CI = 1.2-2.2), which included a statistically significant increase in the risk of presenting to the emergency department (32.9% vs. 19.0%; adjusted RR = 1.6, 95% CI = 1.1-2.2) but not hospital admissions (10.9% vs. 5.0%; adjusted RR = 1.8, 95% CI = 0.9-3.4).The low numbers of events led to imprecision around the estimates.Patients with ADPKD have a higher risk of return to the hospital within 30 days of ureteroscopy for stone disease.We did not register this study.L’urétéroscopie est une option minimalement invasive pour traiter les calculs des voies urinaires hautes. Cependant, les distorsions anatomiques des reins présentes chez les patients atteints de polykystose rénale autosomique dominante (ADPKD) exposent ces derniers à un risque accru de complications liées à la procédure.Comparer le risque de complications liées à l’urétéroscopie chez des patients atteints ou non d’ADPKD dans les 30 jours suivant la procédure.Étude de cohorte rétrospective.Ontario, Canada.L’étude porte sur 73 patients atteints d’ADPKD et 81 445 patients témoins ayant subi une urétéroscopie entre le 1Le risque dans les 30 jours de: 1) visite à l’hôpital pour des complications liées à l’urétéroscopie (résultat composite d’une visite aux urgences ou d’une admission en raison d’une insuffisance rénale aiguë, d’une infection urinaire ou d’un sepsis); 2) toute autre cause de visite à l’hôpital; 3) toute autre cause d’admission; et 4) toute autre cause de visite aux urgences.Une régression de Poisson modifiée a été employée pour l’analyze des résultats sur les variables démographiques, l’utilization des soins de santé au cours de l’année précédente, les différentes procédures et maladies concomitantes liées au résultat au cours des cinq années précédentes et les médicaments prescrits au cours des 120 derniers jours afin de comparer le rapport de risque (RR) de chaque résultat entre les patients atteints ou non d’ADPKD.L’âge médian des sujets (écart interquartile) s’établissait à 44 ans (38-60 ans) dans le groupe de patients ADPKD et à 53 ans (42-64 ans) dans le groupe témoin; les femmes représentaient environ 40 % des sujets dans les deux groupes. Le risque de complications liées à l’urétéroscopie n’était pas significativement différent entre le groupe ADPKD et le groupe témoin (8,2 % vs 4,2 %; RR corrigé: 1,5; IC 95 %: 0,7 à 3,2). Tous les patients, avec ou sans ADPKD, étaient plus susceptibles de se présenter à l’hôpital après l’intervention (36,6 % vs 20,0 %; RR corrigé: 1,6; IC 95 %: 1,2 à 2,2). Ce résultat incluait un risque significativement plus élevé de se présenter aux urgences (32,9 % vs 19,0 %; RR corrigé: 1,6; IC 95 %: 1,1 à 2,2), mais pas d’être hospitalisé (11 % vs 5 %; RR corrigé: 1,8; IC 95 %: 0,9 à 3,4).Le faible nombre d’événements a mené à l’imprécision des estimations.Les patients atteints d’ADPKD présentent un risque accru de retourner à l’hôpital dans les 30 jours suivant une urétéroscopie pour traiter des calculs urinaires.L’étude n’a pas été enregistrée.

Background: Clinical practice guidelines recommend routine kidney function and serum potassium testing within 30 days of initiating ACE (angiotensin-converting enzyme) inhibitor or angiotensin II receptor blocker therapy. However, evidence is lacking about whether follow-up testing reduces therapy-related adverse outcomes. Methods and Results: We conducted 2 population-based retrospective cohort studies in Kaiser Permanente Northern California and Ontario, Canada. Patients with outpatient serum creatinine and potassium tests in the 30 days after starting ACE inhibitor or angiotensin II receptor blocker therapy were matched 1:1 to patients without follow-up tests. We evaluated the association of follow-up testing with 30-day all-cause mortality and hospitalization with acute kidney injury or hyperkalemia using Cox regression. We also developed and externally validated a risk score to identify patients at risk of having abnormally high serum creatinine and potassium values in follow-up. We identified 75 251 matched pairs initiating ACE inhibitor or angiotensin II receptor blocker therapy between January 1, 2007, and December 31, 2017, in Kaiser Permanente Northern California. Follow-up testing was not significantly associated with 30-day all-cause mortality in Kaiser Permanente Northern California (hazard ratio, 0.75 [95% CI, 0.54–1.06]) and was associated with higher mortality in 84 905 matched pairs in Ontario (hazard ratio, 1.32 [95% CI, 1.07–1.62]). In Kaiser Permanente Northern California, follow-up testing was significantly associated with higher rates of hospitalization with acute kidney injury (hazard ratio, 1.66 [95% CI, 1.10–2.22]) and hyperkalemia (hazard ratio, 3.36 [95% CI, 1.08–10.41]), as was observed in Ontario. The risk score for abnormal potassium provided good discrimination (area under the curve [AUC], 0.75) and excellent calibration of predicted risks, while the risk score for abnormal serum creatinine provided moderate discrimination (AUC, 0.62) but excellent calibration. Conclusions: Routine laboratory monitoring after ACE inhibitor or angiotensin II receptor blocker initiation was not associated with a lower risk of 30-day mortality. We identified patient subgroups in which targeted testing may be effective in identifying therapy-related changes in serum potassium or kidney function.

Background Sustained low efficiency dialysis (SLED) has emerged as an alternative to continuous renal replacement therapy (CRRT) for the treatment of acute kidney injury (AKI) in critically ill patients. However, there is limited information on the short- and long-term outcomes of SLED compared to CRRT. Methods We conducted a retrospective cohort study of patients with AKI who commenced either SLED or CRRT in ICUs at a tertiary care hospital in Toronto, Canada. The primary outcome was 90-day all-cause mortality. Secondary outcomes included mortality at one year, and dialysis dependence at 90 days and one year. All outcomes were ascertained by linkage to provincial datasets. Results We identified 284 patients, of whom 95 and 189 commenced SLED and CRRT, respectively. Compared to SLED recipients, more CRRT recipients were mechanically ventilated (96% vs 86%, p = 0.002) and receiving vasopressors (94% vs 84%, p = 0.01) at the time of RRT initiation. At 90 days following RRT initiation, 52 (55%) and 126 (67%) SLED and CRRT recipients, respectively, died (adjusted risk ratio (RR) 0.91, 95% CI 0.75–1.11). There was no inter-modality difference in time to death through 90 days (adjusted hazard ratio 0.90, 95% CI 0.64–1.27). Among patients surviving to Day 90, a higher proportion of SLED recipients remained RRT dependent (10 (23%) vs 6 (10%) CRRT recipients, adjusted RR 2.82, 95% CI 1.02–7.81). At one year, there was no difference in mortality or dialysis dependence. Conclusions Among critically ill patients with acute kidney injury, mortality at 90 days and one year was not different among patients initiating SLED as compared to CRRT.

Introduction: The study’s objective was to examine the effects of renal preservation surgery on long-term mortality, cardiovascular outcomes, and renal-related outcomes. Methods: We performed a retrospective cohort study of all partial (n=575) and radical nephrectomies (n=882) for tumors ≤7 cm in diameter between 2002 and 2010 across three academic centers in Ontario, Canada. We linked records from provincial databases to assess patient characteristics and outcomes (median seven years’ followup using retrospective data). A weighted propensity score was used to reduce confounding. The primary outcome was all-cause mortality. Secondary outcomes included hospitalization with major cardiovascular events, non-cancer related mortality, kidney cancer-related mortality, and dialysis. Results: Mean one-year postoperative estimated glomerular filtration rate (eGFR) was 71 mL/min/1.73 m2 in the partial group and 52 mL/min/1.73 m2 in the radical group. Partial nephrectomy was associated with a lower risk of all-cause mortality in the first five years after surgery (hazard ratio [HR] 0.42; 95% confidence interval [CI] 0.27–0.66), which did not extend beyond five years (HR 1.01; 95% CI 0.68–1.49). Kidney cancer-related mortality was lower in the partial compared to the radical group for the first four years after surgery (HR 0.16; 95% CI 0.04–0.72). There were no significant differences between the groups for cardiovascular outcomes or non-cancer related deaths. Conclusions: Overall survival and cancer-specific survival was reduced in radical nephrectomy patients. However, despite reduced renal function in the radical nephrectomy group, non-cancer -related death, cardiovascular events, and dialysis were not significantly different between groups. Long-term benefits of partial nephrectomy may be less than previously believed.

ObjectivesChronic kidney disease (CKD) is common; therefore, coordination of care between primary care and nephrology is important. Ontario Renal Network’s KidneyWise toolkit was developed to provide guidance on the detection and management of people with CKD in primary care (www.kidneywise.ca). The aim of this study was to evaluate the impact of the April 2015 KidneyWise toolkit release on the characteristics of primary care referrals to nephrology.Design and settingThe study was a prospective pre-post design conducted at two nephrology sites (community site: Trillium Health Partners in Mississauga, Ontario, Canada, and academic site: St Joseph’s Healthcare in Hamilton, Ontario, Canada). Referrals were compared during the 3-month time period immediately prior to, and during a 3-month period 1 year after, the toolkit release.Primary and secondary outcome measuresThe primary outcome was the change in proportion of referrals for CKD that met the KidneyWise criteria. Additional secondary referral and quality of care outcomes were also evaluated. Multivariable logistic regression was used to evaluate preselected variables for their independent association with referrals that met the KidneyWise criteria.ResultsThe proportion of referrals for CKD among people who met the KidneyWise referral criteria did not significantly change from pre-KidneyWise to post-KidneyWise implementation (44.7% vs 45.8%, respectively, adjusted OR 1.16, 95% CI 0.85 to 1.59, p=0.36). The proportion of referrals for CKD that provided a urine albumin-creatinine ratio significantly increased post-KidneyWise (25.8% vs 43.8%, adjusted OR 1.45, 95% CI 1.06 to 1.97, p=0.02). The significant independent predictors of meeting the KidneyWise referral criteria were academic site, increased age and use of the KidneyWise referral form.ConclusionsWe did not observe any change in the proportion of appropriate referrals for CKD at two large nephrology centres 1 year after implementation of the KidneyWise toolkit.

Background Invasive fungal infection (IFI) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. The long-term probability of post-transplant IFI is poorly understood. Methods We conducted a population-based cohort study using linked administrative healthcare databases from Ontario, Canada, to determine the incidence rate; 1-, 5-, and 10-year cumulative probabilities of IFI; and post-IFI all-cause mortality in SOT recipients from 2002 to 2016. We also determined post-IFI, death-censored renal allograft failure. Results We included 9326 SOT recipients (median follow-up: 5.35 years). Overall, the incidence of IFI was 8.3 per 1000 person-years. The 1-year cumulative probability of IFI was 7.4% for lung, 5.4% for heart, 1.8% for liver, 1.2% for kidney-pancreas, and 1.1% for kidney-only allograft recipients. Lung transplant recipients had the highest incidence rate and 10-year probability of IFI: 43.0 per 1000 person-years and 26.4%, respectively. The 1-year all-cause mortality rate after IFI was 34.3%. IFI significantly increased the risk of mortality in SOT recipients over the entire follow-up period (hazard ratio: 6.50, 95% CI: 5.69-7.42). The 1-year probability of death-censored renal allograft failure after IFI was 9.8%. Conclusion Long-term cumulative probability of IFI varies widely among SOT recipients. Lung transplantation was associated with the highest incidence of IFI with considerable 1-year all-cause mortality.

Background Patients undergoing treatment for cancer are at increased risk of acute kidney injury (AKI). There are few data on AKI incidence and risk factors in the current era of cancer treatment. Methods We conducted a population-based study of all patients initiating systemic therapy (chemotherapy or targeted agents) for a new cancer diagnosis in Ontario, Canada (2007–2014). The primary outcome was hospitalization with AKI or acute dialysis. We estimated the cumulative incidence of AKI and fitted Fine and Gray models, adjusting for demographics, cancer characteristics, comorbidities, and coprescriptions. We modeled exposure to systemic therapy (the 90-day period following treatments) as a time-varying covariate. We also assessed temporal trends in annual AKI incidence. Results We identified 163 071 patients initiating systemic therapy of whom 10 880 experienced AKI. The rate of AKI was 27 per 1000 person-years, with overall cumulative incidence of 9.3% (95% CI = 9.1% to 9.6%). Malignancies with the highest 5-year AKI incidence were myeloma (26.0%, 95% CI = 24.4% to 27.7%), bladder (19.0%, 95% CI = 17.6% to 20.5%), and leukemia (15.4%, 95% CI = 14.3% to 16.5%). Advanced cancer stage, chronic kidney disease, and diabetes were associated with increased risk of AKI (adjusted hazard ratios [aHR] = 1.41, 95% CI = 1.28 to 1.54; 1.80, 95% CI = 1.67 to 1.93; and 1.43, 95% CI = 1.37 to 1.50, respectively). In patients aged 66 years or older with universal drug benefits, diuretic, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker coprescription was associated with higher AKI risk (aHR = 1.20, 95% CI = 1.14 to 1.28; 1.30, 95% CI = 1.23 to 1.38). AKI risk was further accentuated during the 90-day period following systemic therapy (aHR = 2.34, 95% CI = 2.24 to 2.45). The annual incidence of AKI increased from 18 to 52 per 1000 person-years between 2007 and 2014. Conclusion Cancer-related AKI is common and associated with advanced stage, chronic kidney disease, diabetes, and concomitant receipt of diuretics or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Risk is heightened in the 90 days after systemic therapy. Preventive strategies are needed to address the increasing burden of AKI in this population.

Background The epidemiology of ESRD requiring maintenance dialysis (ESRD-D) in large, diverse immigrant populations is unclear.Methods We estimated ESRD-D prevalence and incidence among immigrants in Ontario, Canada. Adults residing in Ontario in 2014 were categorized as long-term Canadian residents or immigrants according to administrative health and immigration datasets. We determined ESRD-D prevalence among these adults and calculated age-adjusted prevalence ratios (PRs) comparing immigrants to long-term residents. Among those who immigrated to Ontario between 1991 and 2012, age-adjusted ESRD-D incidence was calculated by world region and country of birth, with immigrants from Western nations as the referent group.Results Among 1,902,394 immigrants and 8,860,283 long-term residents, 1700 (0.09%) and 8909 (0.10%), respectively, presented with ESRD-D. Age-adjusted ESRD-D prevalence was higher among immigrants from sub-Saharan Africa (PR, 2.17; 95% confidence interval [95% CI], 1.84 to 2.57), Latin America and the Caribbean (PR, 2.11; 95% CI, 1.90 to 2.34), South Asia (PR, 1.45; 95% CI, 1.32 to 1.59), and East Asia and the Pacific (PR, 1.34; 95% CI, 1.22 to 1.46). Immigrants from Somalia (PR, 4.18; 95% CI, 3.11 to 5.61), Trinidad and Tobago (PR, 2.88; 95% CI, 2.23 to 3.73), Jamaica (PR, 2.88; 95% CI, 2.40 to 3.44), Sudan (PR, 2.84; 95% CI, 1.53 to 5.27), and Guyana (PR, 2.69; 95% CI, 2.19 to 3.29) had the highest age-adjusted ESRD-D PRs relative to long-term residents. Immigrants from these countries also exhibited higher age-adjusted ESKD-D incidence relative to Western Nations immigrants.Conclusions Among immigrants in Canada, those from sub-Saharan Africa and the Caribbean have the highest ESRD-D risk. Tailored kidney-protective interventions should be developed for these susceptible populations.

Background: We assessed the validity of physician billing codes and hospital admission using International Classification of Diseases 10th revision codes to identify vascular access placement, secondary patency, and surgical revisions in administrative data. Methods: We included adults (≥18 years) with a vascular access placed between 1 April 2004 and 31 March 2013 at the University Health Network, Toronto. Our reference standard was a prospective vascular access database (VASPRO) that contains information on vascular access type and dates of placement, dates for failure, and any revisions. We used VASPRO to assess the validity of different administrative coding algorithms by calculating the sensitivity, specificity, and positive predictive values of vascular access events. Results: The sensitivity (95% confidence interval) of the best performing algorithm to identify arteriovenous access placement was 86% (83%, 89%) and specificity was 92% (89%, 93%). The corresponding numbers to identify catheter insertion were 84% (82%, 86%) and 84% (80%, 87%), respectively. The sensitivity of the best performing coding algorithm to identify arteriovenous access surgical revisions was 81% (67%, 90%) and specificity was 89% (87%, 90%). The algorithm capturing arteriovenous access placement and catheter insertion had a positive predictive value greater than 90% and arteriovenous access surgical revisions had a positive predictive value of 20%. The duration of arteriovenous access secondary patency was on average 578 (553, 603) days in VASPRO and 555 (530, 580) days in administrative databases. Conclusion: Administrative data algorithms have fair to good operating characteristics to identify vascular access placement and arteriovenous access secondary patency. Low positive predictive values for surgical revisions algorithm suggest that administrative data should only be used to rule out the occurrence of an event.

INTRODUCTION AND OBJECTIVES:Partial nephrectomy has become the gold standard for localized renal masses as it provides excellent oncologic control while preserving renal mass and global renal funct...

Clinical outcomes after a hospital discharge are poorly defined for patients receiving maintenance in-center (outpatient) hemodialysis. To describe the proportion and characteristics of these patients who are rehospitalized, visit an emergency department, or die within 30 days after discharge from an acute hospitalization, we conducted a population-based study of all adult patients receiving maintenance in-center hemodialysis who were discharged between January 1, 2003, and December 31, 2011, from 157 acute care hospitals in Ontario, Canada. For patients with more than one hospitalization, we randomly selected a single hospitalization as the index hospitalization. Of the 11,177 patients included in the final cohort, 1926 (17%) were rehospitalized, 2971 (27%) were treated in the emergency department, and 840 (7.5%) died within 30 days of discharge. Complications of type 2 diabetes mellitus were the most common reason for rehospitalization, whereas heart failure was the most common reason for an emergency department visit. In multivariable analysis using a cause-specific Cox proportional hazards model, the following characteristics were associated with 30-day rehospitalization: older age, the number of hospital admissions in the preceding 6 months, the number of emergency department visits in the preceding 6 months, higher Charlson comorbidity index score, and the receipt of mechanical ventilation during the index hospitalization. Thus, a large proportion of patients receiving maintenance in-center hemodialysis will be readmitted or visit an emergency room within 30 days of an acute hospitalization. A focus on improving care transitions from the inpatient setting to the outpatient dialysis unit may improve outcomes and reduce healthcare costs.

It is uncertain how often patients with autosomal dominant polycystic kidney disease (ADPKD) develop kidney stones.To review English-language studies reporting the incidence and prevalence of stones and stone interventions in adults with ADPKD.Systematic review and meta-analysis.Any country of origin.Adult patients with ADPKD.Incidence or prevalence of kidney stones and stone interventions.We reviewed 1812 citations from bibliographic databases, abstracted data from 49 eligible studies, and assessed methodological quality in duplicate. In some studies, the proportion of adults with ADPKD with the outcome were compared to adults without ADPKD; for these studies, prevalence risk ratios were calculated and pooled using a random effects model.We identified 49 articles that met our review criteria. The methodological quality of many studies was limited (scores ranging from 2 to 14 out of 22, with a higher score indicating higher quality). No study clearly reported stone incidence, and in the cross-sectional studies, the definition of stones was often unclear. The prevalence of stones ranged from 3% to 59%, and a prevalence of stone interventions ranged from 1% to 8%; the average patient age at the time of assessment ranged from 26 to 61 years across the studies. Two studies reported a nonstatistically significant higher stone prevalence in patients with ADPKD compared to unaffected family members. Compared to unaffected family members, patients with ADPKD had a higher prevalence of kidney stones (6 cross-sectional studies; unadjusted prevalence ratio: 1.8; 95% confidence interval: 1.3 to 2.6;Studies were limited to articles published in English.The prevalence of kidney stones and stone interventions in adults with ADPKD remains uncertain. Future studies of higher methodological quality are needed to better characterize the incidence and prevalence of kidney stones in patients with ADPKD.We did not register the protocol for this systematic review.La prévalence du développement de calculs rénaux chez les patients atteints de polykystose rénale autosomique dominante (ADPKD) est mal connue.Examiner les études publiées en anglais portant sur l’incidence et la prévalence des calculs rénaux et des interventions liées à ces derniers chez les adultes atteints d’ADPKD.Revue systématique et méta-analyze.Tous les pays d’origine.Des adultes atteints d’ADPKD.L’incidence ou la prévalence des calculs rénaux et des interventions sur ceux-ci.Nous avons examiné 1 812 citations issues des bases de données bibliographiques, extrait les données des 49 études admissibles et analysé leur qualité méthodologique en duplicata. Dans certaines études, la proportion d’adultes atteints d’ADPKD présentant le résultat d’intérêt avait été comparée à celle de sujets non atteints d’ADPKD; dans ces études, les rapports de risque de la prévalence ont été calculés et regroupés à l’aide d’un modèle à effets aléatoires.Nous avons repéré 49 articles satisfaisant nos critères, dont plusieurs étaient de qualité méthodologique limitée (scores entre 2 et 14 sur une possibilité de 22, une note élevée indiquant une meilleure qualité). Aucune étude ne faisait clairement état d’une incidence de calculs rénaux. De plus, la définition des calculs rénaux n’était souvent pas très claire dans les études transversales. La prévalence des calculs rénaux variait entre 3 % et 59 % et celle des interventions liées variait de 1 % à 8 %. L’âge moyen des patients au moment de l’évaluation allait de 26 à 61 ans selon les études. Deux études faisaient état d’une prévalence plus élevée, quoique non statistiquement significative, chez les patients atteints d’ADPKD par rapport aux membres de leurs familles non atteints. De même, six études transversales rapportaient une prévalence plus élevée de calculs rénaux chez les patients atteints d’ADPKD comparé aux membres de leurs familles non atteints (rapport de prévalence non corrigé: 1,8; IC 95 %: 1,3 à 2,6;L’étude ne porte que sur des articles publiés en anglais.La prévalence des calculs rénaux et des interventions relatives à ces derniers demeure mal connue chez les adultes atteints d’ADPKD. Des études supplémentaires et de meilleure qualité méthodologique sont nécessaires afin de mieux caractériser l’incidence et la prévalence des calculs rénaux dans cette population.Le protocole de cette revue systématique n’a pas été enregistré.

Reduced kidney function and distorted kidney anatomy in patients with autosomal dominant polycystic kidney disease (ADPKD) may complicate stone interventions more compared with the general population.To review studies describing the safety and efficacy of the 3 main stone interventions in adults with ADPKD: shock wave lithotripsy (SWL), ureteroscopy, and percutaneous nephrolithotomy (PCNL).Systematic review.Any country of origin.Adults with ADPKD who underwent SWL, ureteroscopy, or PCNL.Being stone free after the intervention and postoperative complications as reported by each study, which included pain, bleeding, and fever.Relevant studies published until February 2019 were identified through a comprehensive search of MEDLINE, EMBASE, Web of Science, BIOSIS PREVIEW, and CINAHL. Studies were eligible for review if they reported at least one outcome following SWL, ureteroscopy, and/or PCNL in adults with ADPKD. We then abstracted information on study characteristics, patient characteristics, intervention details, and postintervention outcomes and assessed the methodological quality of each study using a modified Downs and Black checklist.We screened 221 citations from which we identified 24 studies that met our review criteria. We identified an additional article when manually reviewing the reference list of an included article, yielding a total of 25 studies describing 311 patients (32 SWL, 42 ureteroscopy, and 237 PCNL). The percentage of patients who were stone free after 1 session ranged from 0% to 69% after SWL, 73% to 100% after ureteroscopy, and 45% to 100% after PCNL. The percentage of patients with ADPKD that experienced at least one postoperative complication ranged from 0% to 33% for SWL, 0% to 27% for ureteroscopy, and 0% to 100% for PCNL.The number and quality of studies published to date are limited.The efficacy and safety of stone interventions in patients with ADPKD remains uncertain, with wide-ranging estimates reported in the literature.We did not register the protocol of this systematic review.Les interventions visant à traiter les calculs rénaux sont plus compliquées chez les patients atteints de polykystose rénale autosomique dominante (ADPKD) que dans la population générale en raison de la fonction rénale réduite et des distorsions anatomiques des reins présentes chez ces patients.Passer en revue les études portant sur l’innocuité et l’efficacité des trois principales interventions pour traiter les calculs rénaux chez des adultes atteints d’ADPKD: la lithotripsie par ondes de choc (LOC), l’urétéroscopie et la néphrolithotomie percutanée (NLPC).Revue systématique.Les pays d’origine des études.Des adultes atteints d’ADPKD ayant subi une LOC, une urétéroscopie ou une NLPC.Une intervention réussie (absence de calculs rénaux) et les complications postopératoires rapportées (douleur, hémorragie et fièvre).Une recherche exhaustive sur MEDLINE, EMBASE, Web of Science, BIOSIS PREVIEW et CINAHL a permis de répertorier toutes les études pertinentes publiées jusqu’en février 2019. Les études devaient rapporter minimalement une des mesures d’intérêt à la suite d’une LOC, d’une urétéroscopie ou d’une NLPC chez des adultes atteints d’ADPKD. Les caractéristiques des études, les caractéristiques des patients, les détails de l’intervention et les résultats postopératoires ont été extraits des études retenues. La qualité méthodologique de chaque étude a été mesurée selon la grille d’évaluation de Downs et Black.Des 221 citations répertoriées par la revue de la littérature, 24 études satisfaisaient nos critères d’inclusion. Une 25Le nombre et la qualité des études publiées sur le sujet sont limités.L’efficacité et l’innocuité des interventions visant le retrait de calculs rénaux chez des patients atteints d’ADPKD demeurent incertaines; les estimations rapportées dans la littérature présentent une grande variété.Le protocole de cette revue systématique n’a pas été enregistré.

Background Clinical guidelines caution against nonsteroidal anti-inflammatory drug (NSAID) use in older adults. The study objective was to quantify the 30-day risk of acute kidney injury (AKI) and hyperkalemia in older adults after NSAID initiation and to develop a model to predict these outcomes. Methods We conducted a population-based retrospective cohort study in Ontario, Canada from 2007 to 2015 of patients ≥66 years. We matched 46 107 new NSAID users with 46 107 nonusers with similar baseline health. The primary outcome was 30-day risk of AKI and secondary outcomes were hyperkalemia and all-cause mortality. Results NSAID use versus nonuse was associated with a higher 30-day risk of AKI {380 [0.82%] versus 272 [0.59%]; odds ratio (OR) 1.41 [95% confidence interval (CI) 1.20–1.65]} and hyperkalemia [184 (0.40%) versus 123 (0.27%); OR 1.50 (95% CI 1.20–1.89); risk difference 0.23% (95% CI 0.13–0.34)]. There was no association between NSAID use and all-cause mortality. A prediction model incorporated six predictors of AKI or hyperkalemia: older age, male gender, lower baseline estimated glomerular filtration rate, higher baseline serum potassium, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use or diuretic use. This model had moderate discrimination [C-statistic 0.72 (95% CI 0.70–0.74)] and good calibration. Conclusions In older adults, new NSAID use compared with nonuse was associated with a higher 30-day risk of AKI and hyperkalemia but not all-cause mortality. Prescription NSAID use among many older adults may be safe, but providers should use caution and assess individual risk.

Patients with chronic kidney disease and severely decreased glomerular filtration rate (GFR) are at high risk for kidney failure, cardiovascular disease (CVD) and death. Accurate estimates of risk and timing of these clinical outcomes could guide patient counseling and therapy. Therefore, we developed models using data of 264,296 individuals in 30 countries participating in the international Chronic Kidney Disease Prognosis Consortium with estimated GFR (eGFR)s under 30 ml/min/1.73m(2). Median participant eGFR and urine albumin-to-creatinine ratio were 24 ml/min/1.73m(2) and 168 mg/g, respectively. Using competing-risk regression, random-effect meta-analysis, and Markov processes with Monte Carlo simulations, we developed two- and four-year models of the probability and timing of kidney failure requiring kidney replacement therapy (KRT), a non-fatal CVD event, and death according to age, sex, race, eGFR, albumin-to-creatinine ratio, systolic blood pressure, smoking status, diabetes mellitus, and history of CVD. Hypothetically applied to a 60-year-old white male with a history of CVD, a systolic blood pressure of 140 mmHg, an eGFR of 25 ml/min/1.73m(2) and a urine albumin-to-creatinine ratio of 1000 mg/g, the four-year model predicted a 17% chance of survival after KRT, a 17% chance of survival after a CVD event, a 4% chance of survival after both, and a 28% chance of death (9% as a first event, and 19% after another CVD event or KRT). Risk predictions for KRT showed good overall agreement with the published kidney failure risk equation, and both models were well calibrated with observed risk. Thus, commonly-measured clinical characteristics can predict the timing and occurrence of clinical outcomes in patients with severely decreased GFR.

BACKGROUND: In primary care, patients with chronic kidney disease (CKD) are frequently prescribed excessive doses of antibiotics relative to their kidney function. We examined whether nephrology comanagement is associated with improved prescribing in primary care. METHODS: In a retrospective propensity score–matched cross-sectional study, we studied the appropriateness of antibiotic prescriptions by primary care physicians to Ontarians ≥66 years of age with CKD Stages 4 and 5 (estimated glomerular filtration rate

Objectives Little is known about the health and health-care patterns of patients with diabetes according to their estimated glomerular filtration rates, especially within a publicly funded health-care system. Methods Using linked health-care databases in Ontario, Canada, we performed a population-based study of adults 50 years of age and older (mean age, 68 years) with prevalent diabetes on January 1, 2014. We categorized patients according to their levels of kidney function (estimated glomerular filtration rate ≥90, 60 to 89, 30 to 59, 15 to 29 or Results There were 569,384 patients in our study. Most had estimated glomerular filtration rates between 60 and 89 mL/min/1.73 m2. At baseline, patients with lower kidney function had longer durations of diabetes and more comorbidities. Over 2 years of follow up, they had higher burdens of medical care, excessive diabetes monitoring and were underscreened for diabetes-related complications. Although metabolic control was reasonable across groups, patients with low kidney function had more hospital encounters and more diabetes-related complications. Conclusions Patients with diabetes and low kidney function are a vulnerable population that faces health system challenges and care gaps. Suggestions for policy and practice are discussed.

Several case reports suggest that non-steroidal anti-inflammatory drug (NSAID) use is associated with development of thrombotic microangiopathy (TMA). We conducted a matched population-based case-control study using linked administrative healthcare data in Ontario, Canada to assess the relationship between TMA hospitalization and recent exposure to prescription NSAIDs versus acetaminophen (acetaminophen was chosen as the referent drug because it has no known association with TMA). Cases and controls were drawn from a source population of adults who filled a prescription for either NSAIDs or acetaminophen between 1991 and 2015 (restricted to adults with prescription drug benefits [n = 3.6 million]). We identified 44 eligible cases with a hospital admission for incident TMA and a recent prescription for NSAIDs or acetaminophen. We successfully matched 38 cases (1:4) to 152 controls without TMA on demographics, risk factors for TMA, and indications for NSAID use. Cases and controls were similar with respect to age (71 years) and sex (63% women); however, on average, cases had more comorbidities than controls (12 vs. 14; p

To determine whether combining spinal or epidural anesthesia with general anesthesia (combined anesthesia) reduces major medical complications of elective surgery compared with general anesthesia alone. We conducted a propensity-matched population-based historical cohort study using large healthcare databases from Ontario, Canada. We identified patients undergoing 21 different elective procedures that were amenable to either combined anesthesia or general anesthesia alone in 108 hospitals from 2004 to 2011. We assessed the following four outcomes together as a composite and individually in the 30 days following surgery: acute kidney injury, stroke, myocardial infarction, and all-cause mortality. Prior to matching, we identified 21,701 patients receiving general anesthesia and 8,042 patients receiving combined anesthesia. After matching, our cohort included 12,379 patients. Twenty-eight baseline characteristics were well-matched between the combined (n = 4,773) and general anesthesia groups (n = 7,606). Mean patient age was 66 yr. Relative to general anesthesia alone, combined anesthesia was not associated with a reduced risk for the composite outcome [104/4,773 (2.2%) vs 162/7,606 (2.1%); odds ratio (OR) 0.97; 95% confidence interval (CI) 0.75 to 1.24] or for any of the four component outcomes when examined separately: acute kidney injury (OR 0.93; 95% CI 0.58 to 1.51), stroke (OR 0.79; 95% CI 0.36 to 1.73), myocardial infarction (OR 1.04; 95% CI 0.69 to 1.57), and all-cause mortality (OR 0.91; 95% CI 0.59 to 1.42). The addition of spinal or epidural anesthesia to general anesthesia was not associated with a reduced risk of major medical complications among 21 different elective procedures when compared with general anesthesia alone.

Background Finding relevant articles in large bibliographic databases such as PubMed, Ovid MEDLINE, and EMBASE to inform care and future research is challenging. Articles relevant to chronic kidney disease (CKD) are particularly difficult to find because they are often published under different terminology and are found across a wide range of journal types. Study Design We used computer automation within a diagnostic test assessment framework to develop and validate information search filters to identify CKD articles in large bibliographic databases. Setting & Participants 22,992 full-text articles in PubMed, Ovid MEDLINE, or EMBASE. Index Test 1,374,148 unique search filters. Reference Test We established the reference standard of article relevance to CKD by manual review of all full-text articles using prespecified criteria to determine whether each article contained CKD content or not. We then assessed filter performance by calculating sensitivity, specificity, and positive predictive value for the retrieval of CKD articles. Filters with high sensitivity and specificity for the identification of CKD articles in the development phase (two-thirds of the sample) were then retested in the validation phase (remaining one-third of the sample). Results We developed and validated high-performance CKD search filters for each bibliographic database. Filters optimized for sensitivity reached at least 99% sensitivity, and filters optimized for specificity reached at least 97% specificity. The filters were complex; for example, one PubMed filter included more than 89 terms used in combination, including "chronic kidney disease," "renal insufficiency," and "renal fibrosis." In proof-of-concept searches, physicians found more articles relevant to the topic of CKD with the use of these filters. Limitations As knowledge of the pathogenesis of CKD grows and definitions change, these filters will need to be updated to incorporate new terminology used to index relevant articles. Conclusions PubMed, Ovid MEDLINE, and EMBASE can be filtered reliably for articles relevant to CKD. These high-performance information filters are now available online and can be used to better identify CKD content in large bibliographic databases.

Mortality after AKI is high, but the causes of death are not well described. To better understand causes of death in patients after a hospitalization with AKI and to determine patient and hospital factors associated with mortality, we conducted a population-based study of residents in Ontario, Canada, who survived a hospitalization with AKI from 2003 to 2013. Using linked administrative databases, we categorized cause of death in the year after hospital discharge as cardiovascular, cancer, infection-related, or other. We calculated standardized mortality ratios to compare the causes of death in survivors of AKI with those in the general adult population and used Cox proportional hazards modeling to estimate determinants of death. Of the 156,690 patients included, 43,422 (28%) died in the subsequent year. The most common causes of death were cardiovascular disease (28%) and cancer (28%), with respective standardized mortality ratios nearly six-fold (5.81; 95% confidence interval [95% CI], 5.70 to 5.92) and eight-fold (7.87; 95% CI, 7.72 to 8.02) higher than those in the general population. The highest standardized mortality ratios were for bladder cancer (18.24; 95% CI, 17.10 to 19.41), gynecologic cancer (16.83; 95% CI, 15.63 to 18.07), and leukemia (14.99; 95% CI, 14.16 to 15.85). Along with older age and nursing home residence, cancer and chemotherapy strongly associated with 1-year mortality. In conclusion, cancer-related death was as common as cardiovascular death in these patients; moreover, cancer-related deaths occurred at substantially higher rates than in the general population. Strategies are needed to care for and counsel patients with cancer who experience AKI.

Patients with severely decreased glomerular filtration rate (GFR) (i.e., chronic kidney disease [CKD] G4+) are at increased risk for kidney failure, cardiovascular disease (CVD) events (including heart failure), and death. However, little is known about the variability of outcomes and optimal therapeutic strategies, including initiation of kidney replacement therapy (KRT). Kidney Disease: Improving Global Outcomes (KDIGO) organized a Controversies Conference with an international expert group in December 2016 to address this gap in knowledge. In collaboration with the CKD Prognosis Consortium (CKD-PC) a global meta-analysis of cohort studies (n = 264,515 individuals with CKD G4+) was conducted to better understand the timing of clinical outcomes in patients with CKD G4+ and risk factors for different outcomes. The results confirmed the prognostic value of traditional CVD risk factors in individuals with severely decreased GFR, although the risk estimates vary for kidney and CVD outcomes. A 2- and 4-year model of the probability and timing of kidney failure requiring KRT was also developed. The implications of these findings for patient management were discussed in the context of published evidence under 4 key themes: management of CKD G4+, diagnostic and therapeutic challenges of heart failure, shared decision-making, and optimization of clinical trials in CKD G4+ patients. Participants concluded that variable prognosis of patients with advanced CKD mandates individualized, risk-based management, factoring in competing risks and patient preferences.