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Objective: Effective management of hypertension requires not only medical intervention but also significant patient self-management. The challenge, however, lies in the diversity of patients' personal barriers to managing their condition. The objective of this research is to identify and categorize personalized barriers to hypertension self-management using the TASKS framework (Task, Affect, Skills, Knowledge, Stress). This study aims to enhance patient-centered strategies by aligning support with each patient's specific needs, recognizing the diversity in their unique circumstances, beliefs, emotional states, knowledge levels, and access to resources. This research is based on observations from a single study focused on eight patients, which may have been a part of a larger project., Results: The analysis of transcripts from eight patients and the Global Hypertension Practice Guidelines revealed 69 personalized barriers. These barriers were distributed as follows: emotional barriers (49%), knowledge barriers (24%), logical barriers (17%), and resource barriers (10%). The findings highlight the significant impact of emotional and knowledge-related challenges on hypertension self-management, including difficulties in home blood pressure monitoring and the use of monitoring tools. This study emphasizes the need for tailored interventions to address these prevalent barriers and improve hypertension management outcomes., (© 2024. The Author(s).)

Background: Case identification is important for health services research, measuring health system performance and risk adjustment, but existing methods based on manual chart review or diagnosis codes can be expensive, time consuming or of limited validity. We aimed to develop a hypertension case definition in electronic medical records (EMRs) for inpatient clinical notes using machine learning., Methods: A cohort of patients 18 years of age or older who were discharged from 1 of 3 Calgary acute care facilities (1 academic hospital and 2 community hospitals) between Jan. 1 and June 30, 2015, were randomly selected, and we compared the performance of EMR phenotype algorithms developed using machine learning with an algorithm based on the Canadian version of the International Statistical Classification of Diseases and Related Health Problems , 10th Revision (ICD), in identifying patients with hypertension. Hypertension status was determined by chart review, the machine-learning algorithms used EMR notes and the ICD algorithm used the Discharge Abstract Database (Canadian Institute for Health Information)., Results: Of our study sample ( n = 3040), 1475 (48.5%) patients had hypertension. The group with hypertension was older (median age of 71.0 yr v. 52.5 yr for those patients without hypertension) and had fewer females (710 [48.2%] v. 764 [52.3%]). Our final EMR-based models had higher sensitivity than the ICD algorithm (> 90% v. 47%), while maintaining high positive predictive values (> 90% v. 97%)., Interpretation: We found that hypertension tends to have clear documentation in EMRs and is well classified by concept search on free text. Machine learning can provide insights into how and where conditions are documented in EMRs and suggest nonmachine-learning phenotypes to implement., Competing Interests: Competing interests: None declared., (© 2023 CMA Impact Inc. or its licensors.)

Risk prediction models are frequently used to identify individuals at risk of developing hypertension. This study evaluates different machine learning algorithms and compares their predictive performance with the conventional Cox proportional hazards (PH) model to predict hypertension incidence using survival data. This study analyzed 18,322 participants on 24 candidate features from the large Alberta's Tomorrow Project (ATP) to develop different prediction models. To select the top features, we applied five feature selection methods, including two filter-based: a univariate Cox p-value and C-index; two embedded-based: random survival forest and least absolute shrinkage and selection operator (Lasso); and one constraint-based: the statistically equivalent signature (SES). Five machine learning algorithms were developed to predict hypertension incidence: penalized regression Ridge, Lasso, Elastic Net (EN), random survival forest (RSF), and gradient boosting (GB), along with the conventional Cox PH model. The predictive performance of the models was assessed using C-index. The performance of machine learning algorithms was observed, similar to the conventional Cox PH model. Average C-indexes were 0.78, 0.78, 0.78, 0.76, 0.76, and 0.77 for Ridge, Lasso, EN, RSF, GB and Cox PH, respectively. Important features associated with each model were also presented. Our study findings demonstrate little predictive performance difference between machine learning algorithms and the conventional Cox PH regression model in predicting hypertension incidence. In a moderate dataset with a reasonable number of features, conventional regression-based models perform similar to machine learning algorithms with good predictive accuracy., (© 2023. The Author(s).)

Background: Prognostic information for patients with hypertension is largely based on population averages. The purpose of this study was to compare the performance of four machine learning approaches for personalized prediction of incident hospitalization for cardiovascular disease among newly diagnosed hypertensive patients., Methods: Using province-wide linked administrative health data in Alberta, we analyzed a cohort of 259,873 newly-diagnosed hypertensive patients from 2009 to 2015 who collectively had 11,863 incident hospitalizations for heart failure, myocardial infarction, and stroke. Linear multi-task logistic regression, neural multi-task logistic regression, random survival forest and Cox proportional hazard models were used to determine the number of event-free survivors at each time-point and to construct individual event-free survival probability curves. The predictive performance was evaluated by root mean squared error, mean absolute error, concordance index, and the Brier score., Results: The random survival forest model has the lowest root mean squared error value at 33.94 and lowest mean absolute error value at 28.37. Machine learning methods provide similar discrimination and calibration in the personalized survival prediction of hospitalizations for cardiovascular events in patients with hypertension. Neural multi-task logistic regression model has the highest concordance index at 0.8149 and lowest Brier score at 0.0242 for the personalized survival prediction., Conclusions: This is the first personalized survival prediction for cardiovascular diseases among hypertensive patients using administrative data. The four models tested in this analysis exhibited a similar discrimination and calibration ability in predicting personalized survival prediction of hypertension patients., (© 2022. The Author(s).)

Identifying high-risk individuals for targeted intervention may prevent or delay hypertension onset. We developed a hypertension risk prediction model and subsequent risk sore among the Canadian population using measures readily available in a primary care setting. A Canadian cohort of 18,322 participants aged 35-69 years without hypertension at baseline was followed for hypertension incidence, and 625 new hypertension cases were reported. At a 2:1 ratio, the sample was randomly divided into derivation and validation sets. In the derivation sample, a Cox proportional hazard model was used to develop the model, and the model's performance was evaluated in the validation sample. Finally, a risk score table was created incorporating regression coefficients from the model. The multivariable Cox model identified age, body mass index, systolic blood pressure, diabetes, total physical activity time, and cardiovascular disease as significant risk factors (p < 0.05) of hypertension incidence. The variable sex was forced to enter the final model. Some interaction terms were identified as significant but were excluded due to their lack of incremental predictive capacity. Our model showed good discrimination (Harrel's C-statistic 0.77) and calibration (Grønnesby and Borgan test, [Formula: see text] statistic = 8.75, p = 0.07; calibration slope 1.006). A point-based score for the risks of developing hypertension was presented after 2-, 3-, 5-, and 6 years of observation. This simple, practical prediction score can reliably identify Canadian adults at high risk of developing incident hypertension in the primary care setting and facilitate discussions on modifying this risk most effectively., (© 2022. The Author(s).)

Objective: We aimed to identify existing hypertension risk prediction models developed using traditional regression-based or machine learning approaches and compare their predictive performance., Methods: We systematically searched MEDLINE, EMBASE, Web of Science, Scopus, and the grey literature for studies predicting the risk of hypertension among the general adult population. Summary statistics from the individual studies were the C-statistic, and a random-effects meta-analysis was used to obtain pooled estimates. The predictive performance of pooled estimates was compared between traditional regression-based models and machine learning-based models. The potential sources of heterogeneity were assessed using meta-regression, and study quality was assessed using the PROBAST (Prediction model Risk Of Bias ASsessment Tool) checklist., Results: Of 14,778 articles, 52 articles were selected for systematic review and 32 for meta-analysis. The overall pooled C-statistics was 0.75 [0.73-0.77] for the traditional regression-based models and 0.76 [0.72-0.79] for the machine learning-based models. High heterogeneity in C-statistic was observed. The age (p = 0.011), and sex (p = 0.044) of the participants and the number of risk factors considered in the model (p = 0.001) were identified as a source of heterogeneity in traditional regression-based models., Conclusion: We attempted to provide a comprehensive evaluation of hypertension risk prediction models. Many models with acceptable-to-good predictive performance were identified. Only a few models were externally validated, and the risk of bias and applicability was a concern in many studies. Overall discrimination was similar between models derived from traditional regression analysis and machine learning methods. More external validation and impact studies to implement the hypertension risk prediction model in clinical practice are required., Competing Interests: The authors have declared that no competing interests exist.

Background: Hypertension is a common chronic condition affecting nearly a quarter of Canadians. Hypertension surveillance in Canada typically relies on administrative data and/or national surveys. Routinely-captured data from primary care electronic medical records (EMRs) are a complementary source for chronic disease surveillance, with longitudinal patient-level details such as sociodemographics, blood pressure, weight, prescribed medications, and behavioural risk factors. As EMR data are generated from patient care and administrative tasks, assessing data quality is essential before using for secondary purposes. This study evaluated the quality of primary care EMR data from one province in Canada within the context of hypertension surveillance., Methods: We conducted a cross-sectional, descriptive study using primary care EMR data collected by two practice-based research networks in Alberta, Canada. There were 48,377 adults identified with hypertension from 53 clinics as of June 2018. Summary statistics were used to examine the quality of data elements considered relevant for hypertension surveillance., Results: Patient year of birth and sex were complete, but other sociodemographic information (ethnicity, occupation, education) was largely incomplete and highly variable. Height, weight, body mass index and blood pressure were complete for most patients (over 90%), but a small proportion of outlying values indicate data inaccuracies were present. Most patients had a relevant laboratory test present (e.g. blood glucose/glycated hemoglobin, lipid profile), though a very small proportion of values were outside a biologically plausible range. Details of prescribed antihypertensive medication, such as start date, strength, dose, frequency, were mostly complete. Nearly 80% of patients had a smoking status recorded, though only 66% had useful information (i.e. categorized as current, past, or never), and less than half had their alcohol use described; information related to amount, frequency or duration was not available., Conclusions: Blood pressure and prescribed medications in primary care EMR data demonstrated good completeness and plausibility, and contribute valuable information for hypertension epidemiology and surveillance. The use of other clinical, laboratory, and sociodemographic variables should be used carefully due to variable completeness and suspected data errors. Additional strategies to improve these data at the point of entry and after data extraction (e.g. statistical methods) are required.

Background Nonpharmacologic interventions that modify lifestyle can lower blood pressure (BP) and have been assessed in numerous randomized controlled trials and pairwise meta-analyses. It is still unclear which intervention would be most efficacious. Methods and Results Bayesian network meta-analyses were performed to estimate the comparative effectiveness of different interventions for lowering BP. From 60 166 potentially relevant articles, 120 eligible articles (14 923 participants) with a median follow-up of 12 weeks, assessing 22 nonpharmacologic interventions, were included. According to the surface under the cumulative ranking probabilities and Grading of Recommendations Assessment, Development and Evaluation (GRADE) quality of evidence, for adults with prehypertension to established hypertension, high-quality evidence indicated that the Dietary Approach to Stop Hypertension (DASH) was superior to usual care and all other nonpharmacologic interventions in lowering systolic BP (weighted mean difference, 6.97 mm Hg; 95% credible interval, 4.50-9.47) and diastolic BP (weighted mean difference, 3.54 mm Hg; 95% credible interval, 1.80-5.28). Compared with usual care, moderate- to high-quality evidence indicated that aerobic exercise, isometric training, low-sodium and high-potassium salt, comprehensive lifestyle modification, breathing-control, and meditation could lower systolic BP and diastolic BP. For patients with hypertension, moderate- to high-quality evidence suggested that the interventions listed (except comprehensive lifestyle modification) were associated with greater systolic BP and diastolic BP reduction than usual care; salt restriction was also effective in lowering both systolic BP and diastolic BP. Among overweight and obese participants, low-calorie diet and low-calorie diet plus exercise could lower more BP than exercise. Conclusions DASH might be the most effective intervention in lowering BP for adults with prehypertension to established hypertension. Aerobic exercise, isometric training, low-sodium and high-potassium salt, comprehensive lifestyle modification, salt restriction, breathing-control, meditation and low-calorie diet also have obvious effects on BP reduction.

Objective: To describe the process for linking electronic medical record (EMR) and administrative data in Alberta and examine the advantages and limitations of utilising linked data for hypertension surveillance., Methods: De-identified EMR data from 323 primary care providers contributing to the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) in Alberta were used. Mapping files from each contributing provider were generated from their EMR to facilitate linkage to administrative data within the provincial health data warehouse. Deterministic linkage was conducted using valid personal healthcare number (PHN) with age and/or sex. Characteristics of patients and providers in the linked cohort were compared with population-level sources. Criteria used to define hypertension in both sources were examined., Results: Data were successfully linked for 6307 hypertensive patients (96.2% of eligible patients) from 49 contributing providers. Non-linkages from invalid PHN (n=246) occurred more for deceased patients and those with fewer primary care encounters, with differences due to type of EMR and patient EMR status. The linked cohort had more patients who were female, >60 years and residing in rural areas compared to the provincial healthcare registry. Family physicians were more often female and medically trained in Canada compared to all physicians in Alberta. Most patients (>97%) had ≥1 record in the registry, pharmacy, emergency/ambulatory care and claims databases; 44.3% had ≥1 record in the hospital discharge database., Conclusion: EMR-administrative data linkage has the potential to enhance hypertension surveillance. The current linkage process in Alberta is limited and subject to selection bias. Processes to address these deficiencies are under way., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Hypertension is one of the most common medical conditions and represents a major risk factor for heart attack, stroke, kidney disease and mortality. The risk of progression to hypertension depends on several factors, and combining these risk factors into a multivariable model for risk stratification would help to identify high-risk individuals who should be targeted for healthy behavioural changes and/or medical treatment to prevent the development of hypertension. The risk prediction models can be further improved in terms of accuracy by using a metamodel updating technique where existing hypertension prediction models can be updated by combining information available in existing models with new data. A systematic review and meta-analysis will be performed of hypertension prediction models in order to identify known risk factors for high blood pressure and to summarise the magnitude of their association with hypertension., Methods and Analysis: MEDLINE, Embase, Web of Science, Scopus and grey literature will be systematically searched for studies predicting the risk of hypertension among the general population. The search will be based on two key concepts: hypertension and risk prediction. The summary statistics from the individual studies will be the regression coefficients of the hypertension risk prediction models, and random-effect meta-analysis will be used to obtain pooled estimates. Heterogeneity and publication bias will be assessed, along with study quality, which will be assessed using the Prediction Model Risk of Bias Assessment Tool checklist., Ethics and Dissemination: Ethics approval is not required for this systematic review and meta-analysis. We plan to disseminate the results of our review through journal publications and presentations at applicable platforms., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Importance: The 2017 American College of Cardiology and American Heart Association (ACC/AHA) blood pressure (BP) guidelines redefined hypertension using a BP threshold of 130/80 mm Hg or greater and applied a treatment target of less than 130/80 mm Hg., Objective: To evaluate the potential change in the diagnosis, treatment, and control of hypertension in a Canadian cohort of patients with hypertension attending primary care practices using the ACC/AHA guidelines., Design, Setting, and Participants: This cross-sectional study used primary care practices across Canada electronic medical record data from the Canadian Primary Care Sentinel Surveillance Network, extracted as of June 30, 2015. Adults with at least 1 primary care encounter in the previous 2 years (July 1, 2013, to June 30, 2015) were included in the study. Those with current hypertension were identified using a validated definition consisting of diagnoses, billing codes, and/or antihypertensive medication from within the primary care electronic medical record. Data analysis was conducted from December 2017 to July 2018., Main Outcomes and Measures: Proportion of individuals with a diagnosis of hypertension, prescribed antihypertensive medication, and meeting treatment BP targets., Results: Of the 594 492 Canadian participants included in the study, 144 348 (24.2%) had hypertension (45.6% male; mean [SD] age, 65.5 [14.5] years). On applying the ACC/AHA guidelines, 252 279 individuals (42.4%) were considered hypertensive and half (51.0%; 95% CI, 50.8%-51.2%) were prescribed an antihypertensive medication. Individuals who were not previously considered to have hypertension but were reclassified as having elevated BP using the lower cutoff of 130/80 mm Hg or greater tended to be younger and were at lower cardiovascular risk. There was a shift toward more individuals requiring antihypertensive treatment, particularly in the lower-risk categories. The crude prevalence of hypertension increased from 13.3% to 32.0% in those aged 18 to 64 years, and of those aged 65 years and older, 16.6% more individuals were reclassified as having hypertension (from 55.2% to 71.8%). Only 12.3% of those who were considered at high risk were reclassified as hypertensive., Conclusions and Relevance: Adoption of the ACC/AHA BP guidelines would result in a near doubling in the prevalence of hypertension in Canada. The changes would largely affect individuals who are younger and at low to moderate cardiovascular risk.

Background: The Systolic Blood Pressure Intervention Trial (SPRINT) showed significant reductions in major cardiovascular events and all-cause mortality with a systolic blood pressure (BP) goal of < 120 mm Hg compared with < 140 mm Hg. We sought to determine the proportion of Canadian adults who meet SPRINT eligibility criteria., Methods: We conducted a cross-sectional study using cycles 1-3 of the nationally representative Canadian Health Measures Survey to estimate the prevalence and characteristics of Canadian adults between the ages of 20 and 79 who meet SPRINT eligibility criteria: age ≥ 50 years, elevated systolic BP of 130-180 mm Hg, and increased cardiovascular risk (with chronic kidney disease, Framingham Risk Score ≥ 15% in 10 years, and/or cardiovascular disease) but without diabetes, stroke, or end-stage renal disease., Results: An estimated 1.3 million (5.2%) Canadian adults met SPRINT eligibility criteria; 14.3% (95% confidence interval, 10.6%-17.9%), or 182,600 people, were not previously considered to have hypertension or need for antihypertensive therapy. Of adults aged 50-79 years treated for hypertension, 18.7% (95% confidence interval, 15.5%-21.8%), or 754,400 individuals, would potentially benefit from treatment intensification., Conclusions: If fully implemented, intensive systolic BP lowering to < 120 mm Hg in SPRINT-eligible high-risk individuals would substantially increase the proportion of Canadian adults receiving BP treatment initiation or intensification., (Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Vascular dementia (VaD) is the second most common form of dementia. However, there were mixed evidences about the association between blood pressure (BP) and risk of VaD in midlife and late life and limited evidence on the association between pulse pressure and VaD., Methods: This is a population-based observational study. 265,897 individuals with at least one BP measurement between the ages of 60 to 65 years and 211,116 individuals with at least one BP measurement between the ages of 70 to 75 years were extracted from The Health Improvement Network in United Kingdom. Blood pressures were categorized into four groups: normal, prehypertension, stage 1 hypertension, and stage 2 hypertension. Cases of VaD were identified from the recorded clinical diagnoses. Multivariable survival analysis was used to adjust other confounders and competing risk of death. All the analysis were stratified based on antihypertensive drug use status. Multiple imputation was used to fill in missing values., Results: After accounting for the competing risk of death and adjustment for potential confounders, there was an association between higher BP levels in the age 60-65 cohort with the risk of developing VaD (hazard ratio [HR] 1.53 (95% confidence interval: 1.04, 2.25) for prehypertension, 1.90 (1.30, 2.78) for stage 1 hypertension, and 2.19 (1.48, 3.26) for stage 2 hypertension) in the untreated group. There was no statistically significant association between BP levels and VaD in the treated group in the age 60-65 cohort and age 70-75 cohort. Analysis on Pulse Pressure (PP) stratified by blood pressure level showed that PP was not independently associated with VaD., Conclusion: High BP between the ages of 60 to 65 years is a significant risk for VaD in late midlife. Greater efforts should be placed on early diagnosis of hypertension and tight control of BP for hypertensive patients for the prevention of VaD.

Background: With high-quality community-based primary care, hospitalizations for ambulatory care sensitive conditions (ACSC) are considered avoidable. The purpose of this study was to test the inter-physician reliability of judgments of avoidable hospitalizations for one ACSC, uncomplicated hypertension, derived from medical chart review., Methods: We applied the Canadian Institute for Health Information's case definition to obtain a random sample of patients who had an ACSC hospitalization for uncomplicated hypertension in Calgary, Alberta. Medical chart review was conducted by three experienced internal medicine specialists. Implicit methods were used to judge avoidability of hospitalization using a validated 5-point scale., Results: There was poor agreement among three physicians raters when judging the avoidability of 82 ACSC hospitalizations for uncomplicated hypertension (κ = 0.092). The κ also remained low when assessing agreement between raters 1 and 3 (κ = 0.092), but the κ was lower (less than chance agreement) for raters 1 and 2 (κ = -0.119) and raters 2 and 3 (κ = -0.008). When the 5-point scale was dichotomized, there was fair agreement among three raters (κ = 0.217). The proportion of ACSC hospitalizations for uncomplicated hypertension that were rated as avoidable was 32.9%, 6.1% and 26.8% for raters 1, 2, and 3, respectively., Conclusions: This study found a low proportion of ACSC hospitalization were rated as avoidable, with poor to fair agreement of judgment between physician raters. This suggests that the validity and utility of this health indicator is questionable. It points to a need to abandon the use of ACSC entirely; or alternatively to work on the development of explicit criteria for judging avoidability of hospitalization for ACSC such as hypertension.

Background: Whether calcium channel blockers exert a greater effect on cardiovascular risk reduction in Asian populations than other antihypertensive agents is unclear. We conducted a meta-analysis of hypertension trials of dihydropyridine calcium channel blockers in Asian populations to clarify this association., Methods: EMBASE, MEDLINE, and Cochrane databases were searched (from inception to August 2016) for randomized controlled trials on cardiovascular death, major adverse cardiovascular events, stroke, congestive heart failure, and coronary revascularization in Asian persons with hypertension. We identified 9 trials that reported data specific to Asian populations (N = 29,643). These trials included 1 placebo-controlled trial and 8 active comparator trials; of these, 5 had angiotensin receptor blockers as the active comparator., Results: One placebo-controlled trial (n = 9711) showed significantly reduced cardiovascular mortality, major adverse cardiovascular events, and stroke with calcium channel blockers. Among 8 active comparator trials (n = 19,932), there were no significant differences in mortality (relative risk [RR], 1.10; 95% confidence interval [CI], 0.72-1.67; I 2  = 0.0%), major adverse cardiovascular events (RR, 1.02; 95% CI, 0.90-1.15; I 2  = 0.0%), stroke (RR, 0.97; 95% CI, 0.80-1.17; I 2  = 0.0%), congestive heart failure (RR, 1.01; 95% CI, 0.51-2.00; I 2  = 53.7), or coronary revascularization rates (RR, 0.98; 95% CI, 0.76-1.25; I 2  = 0.0%) in the calcium channel blocker group compared with other antihypertensive agents. When restricting the meta-analysis to angiotensin receptor blocker comparators (n = 10,384), there were no significant differences in cardiovascular outcomes., Conclusions: There is no evidence that dihydropyridine calcium channel blockers are superior to other antihypertensive agents in Asian populations for the treatment of hypertension., (Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Though pharmacy claims data are commonly used to study medication adherence, there remains no standard operational definition for adherence especially for patients on multiple medications. Even when studies use the same terminology, the actual methods of calculating adherence can differ drastically. It is unclear whether the use of different definitions results in different conclusions regarding adherence and associated outcomes. The objective of our study was to compare adherence rates and associations with mortality using different operational definitions of adherence, and using various methods of handling concurrent medication use., Methods: We conducted a cohort study of patients aged ≥65 years from Manitoba, Canada, with incident hypertension diagnosed in 2004 and followed to 2009. We calculated adherence rates to anti-hypertensive medications using different operational definitions of medication adherence (including interval and prescription based medication possession ratios [MPR] and proportion of days covered [PDC]). For those on concurrent medications, we calculated adherence rates using the different methods of handling concurrent medication use, for each definition. We used logistic regression to determine the association between adherence and mortality for each operational definition., Results: Among 2199 patients, 24.1% to 90.5% and 71.2% to 92.7% were considered adherent when using fixed interval and prescription-based interval medication possession ratios [MPRi and MPRp] respectively, depending on how concurrent medications were handled. Adherence was inversely associated with death, with the strongest association for MPRp measures. This association was significant only when considering adherence to any anti-hypertensive [aOR 0.70, 95% CI 0.51, 0.97], or when the mean of the class-specific MPRp's [adjusted OR 0.71, 95% CI 0.53, 0.95] was used. No significant association existed when the highest or lowest class-specific MPRp was used as the adherence estimate., Conclusion: The range of adherence estimates varies widely depending on the operational definition used. Given less variation in adherence rates and their stronger association against mortality, we recommend using prescription-based MPR's to define medication adherence.

Background: To assess the use of updated comorbidity information over time on ability to predict mortality among adults with newly diagnosed hypertension., Methods: We studied adults 18 years and older with an incident diagnosis of hypertension from Alberta, Canada. We compared the prognostic performance of Cox regression models using Charlson comorbidities as time-invariant covariates at baseline (TIC) versus models including Charlson comorbidities as time-varying covariates (TVC) using Akaike Information Criterion (AIC) for testing goodness of fit., Results: The strength of the association between important prognostic clinical variables and mortality varied by modeling technique; for example, myocardial infarction was less strongly associated with mortality in the TIC model (Hazard Ratio 1.07; 95% Confidence Interval (CI): 1.05 to 1.1) than in the TVC model (HR 1.20; 95% CI: 1.18 to 1.22). All TVC models slightly outperformed TIC models, regardless of the method used to adjust for comorbid conditions (individual Charlson Comorbidities, count of comorbidities or indices). The TVC model including all 17 Charlson comorbidities as individual independent variables showed the best fit and performance., Conclusion: Accounting for changes in patient comorbidity status over time more accurately captures a patient's health risk and slightly improves predictive model fit and performance than traditional methods using TIC assessment.

Background: Electronic medical records (EMR) can be a cost-effective source for hypertension surveillance. However, diagnosis of hypertension in EMR is commonly under-coded and warrants the needs to review blood pressure and antihypertensive drugs for hypertension case identification., Methods: We included all the patients actively registered in The Health Improvement Network (THIN) database, UK, on 31 December 2011. Three case definitions using diagnosis code, antihypertensive drug prescriptions and abnormal blood pressure, respectively, were used to identify hypertension patients. We compared the prevalence and treatment rate of hypertension in THIN with results from Health Survey for England (HSE) in 2011., Results: Compared with prevalence reported by HSE (29.7%), the use of diagnosis code alone (14.0%) underestimated hypertension prevalence. The use of any of the definitions (38.4%) or combination of antihypertensive drug prescriptions and abnormal blood pressure (38.4%) had higher prevalence than HSE. The use of diagnosis code or two abnormal blood pressure records with a 2-year period (31.1%) had similar prevalence and treatment rate of hypertension with HSE., Conclusions: Different definitions should be used for different study purposes. The definition of 'diagnosis code or two abnormal blood pressure records with a 2-year period' could be used for hypertension surveillance in THIN., (© The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: To determine the data sources and 'look back' intervals to define comorbidities., Data Sources: Hospital discharge abstracts database (DAD), physician claims, population registry and death registry from April 1, 1994 to March 31, 2010 in Alberta, Canada., Study Design: Newly-diagnosed hypertension cases from 1997 to 2008 fiscal years were identified and followed up to 12 years. We defined comorbidities using data sources and duration of retrospective observation (6 months, 1 year, 2 years, and 3 years). The C-statistics for logistic regression and concordance index (CI) for Cox model of mortality and cardiovascular disease hospitalization were used to evaluate discrimination performance for each approach of defining comorbidities., Principal Findings: The comorbidities prevalence became higher with a longer duration. Using DAD alone underestimated the prevalence by about 75%, compared to using both DAD and physician claims. The C-statistic and CI were highest when both DAD and physician claims were used, and model performance improved when observation duration increased from 6 months to one year or longer., Conclusion: The comorbidities prevalence is greatly impacted by the data source and duration of retrospective observation. A combination of DAD and physicians claims with at least one year observation duration improves predictions for cardiovascular disease and one-year mortality outcome model performance., Competing Interests: Salary support for H.Q. and F.M. is from Alberta Innovates – Health Solutions. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials.

Background: Traditional Chinese medicine (TCM) including Chinese herbal therapy has been widely practiced in China. However, little is known about Chinese herbal therapy use for hypertension management, which is one of the most prevalent chronic conditions in China. Thus we described Chinese herbal therapy and western drug users, beliefs, hypertension knowledge, and Chinese herbal and western drug adherence and determinants of Chinese herbal therapy use among patients with hypertension in rural areas of Heilongjiang Province, China., Methodology and Principal Findings: This face-to-face cross sectional survey included 665 hypertensive respondents aged 30 years or older in rural areas of Heilongjiang Province, China. Of 665 respondents, 39.7% were male, 27.4% were aged 65 years or older. At the survey, 14.0% reported using Chinese herbal therapy and 71.3% reported using western drug for hypertension management. A majority of patients had low level of treatment adherence (80.6% for the Chinese herbal therapy users and 81.2% for the western drug users). When respondents felt that their blood pressure was under control, 72.0% of the Chinese herbal therapy users and 69.2% of the western drug users sometimes stopped taking their medicine. Hypertensive patients with high education level or better quality of life are more likely use Chinese herbal therapy., Conclusions and Significance: Majority of patients diagnosed with hypertension use western drugs to control blood pressure. Chinese herbal therapy use was associated with education level and quality of life.

Administrative health data have been used in hypertension surveillance using the 1H2P method: the International Classification of Disease (ICD) hypertension diagnosis codes were recorded in at least 1 hospitalization or 2 physician claims within 2 year-period. Accumulation of false positive cases over time using the 1H2P method could result in the overestimation of hypertension prevalence. In this study, we developed and validated a new reclassification method to define hypertension cases using regularized logistic regression with the age, sex, hypertension and comorbidities in physician claims, and diagnosis of hypertension in hospital discharge data as independent variables. A Bayesian method was then used to adjust the prevalence estimated from the reclassification method. We evaluated the hypertension prevalence in data from Alberta, Canada using the currently accepted 1H2P method and these newly developed methods. The reclassification method with Bayesian adjustment produced similar prevalence estimates as the 1H2P method. This supports the continued use of the 1H2P method as a simple and practical way to conduct hypertension surveillance using administrative health data.

Background: Hospitalizations for ambulatory care-sensitive conditions (ACSCs) represent an indirect measure of access and quality of community care. The purpose of this study was to examine the association between one ACSC, uncomplicated hypertension, and previous primary care physician (PCP) utilization., Methods: A cohort of patients with hypertension was identified using administrative databases in Alberta between fiscal years 1994 and 2008. We applied the Canadian Institute for Health Information's case definition to detect patients with uncomplicated hypertension as the most responsible reason for hospitalization and/or Emergency Department (ED) visit. We assessed hypertension-related and all-cause PCP visits., Results: The overall adjusted rate of ACSC hospitalizations and ED visits for uncomplicated hypertension was 7.1 and 13.9 per 10,000 hypertensive patients, respectively. The likelihood of ACSC hospitalization for uncomplicated hypertension was associated with age, household income quintile, region of residence, and Charlson comorbidity status (all P < 0.0001). The adjusted rate of ACSC hospitalizations for uncomplicated hypertension increased from 4.8 per 10,000 hypertensive patients for those without hypertension-related PCP visits before diagnosis to 10.5 per 10,000 hypertensive patients for those with 5 or more hypertension-related PCP visits. The rate of ACSC hospitalizations and/or ED visits for uncomplicated hypertension increased as the number of hypertension-related PCP visits increased even after stratifying according to demographic and clinical characteristics., Conclusions: As the frequency of hypertension-related PCP visits increased, the rate of ACSC hospitalizations and/or ED visits for uncomplicated hypertension increased. This suggests that ACSC hospitalization for uncomplicated hypertension might not be a particularly good indicator for access to primary care., (Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Few studies have evaluated adherence to antihypertensive medication in Chinese and South Asian populations and little is known about the long-term outcome. Our objectives were to compare adherence to antihypertensive medications and assess the association of adherence and long-term mortality in Chinese, South Asian, and white patients with newly diagnosed hypertension., Methods: We conducted a retrospective cohort study of patients with hypertension who were new users of antihypertensive medications (1997-2005) using administrative data and a province-wide prescription database from British Columbia, Canada. Antihypertensive medication adherence within 1 year from the date of the first antihypertensive drug prescription was assessed using the 'proportion of days covered' metric. Proportion of days covered ≥ 80% indicated optimal adherence. Patients were followed for up to 10 years for mortality., Results: There were 16,471 (11.1%) Chinese, 6099 (4.1%) South Asian, and 126,081 (84.8%) white patients who were prescribed antihypertensive medications. Compared with white patients, Chinese (odds ratio, 0.69; 95% confidence interval [CI], 0.67-0.72) and South Asian patients (odds ratio, 0.38; 95% CI, 0.36-0.40) were less likely to be optimally adherent to antihypertensive medications. Optimal adherence was associated with reduced mortality in white patients (risk-adjusted hazard ratio [aHR], 0.89; 95% CI, 0.85-0.93) but not associated with mortality in Chinese (aHR, 0.98; 95% CI, 0.83-1.17) and South Asian patients (aHR, 1.10; 95% CI, 0.84-1.44)., Conclusions: Chinese and South Asian patients with newly diagnosed hypertension were significantly less likely to adhere to antihypertensive medications than their white counterparts. However, optimal adherence in Chinese and South Asian patients was not associated with mortality., (Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: To describe aspects of prevalence and incidence of hypertension in Canada., Recent Findings: Three databases have been used to determine prevalence and incidence of hypertension in Canada. Estimates of burden of hypertension varied by methods of data collection. The prevalence amongst adults was 23% based on administrative data in 2007 (which rely on physician diagnosis, but captures all adults, including those living in institutions or long-term care facilities), 18% based on self-report in the Canadian Community Health Survey in 2007 and 19% based on physical measurements in community-dwelling adults in the Canadian Health Measures Survey in 2007-2009. In the absence of a large representative prospective cohort study, incidence in Canada can only be estimated using administrative data., Summary: Representativeness and validity of these available national data are questionable for determining accurate prevalence and incidence of hypertension. The important selection criteria for these data limit their generalizability. Linkage of surveys, administrative data and electronic health records could provide rich data for determining a more accurate representation of hypertension in Canada.

Background: Access to a primary care physician (PCP) improves health outcomes among patients with hypertension. The study objective was to compare PCP use among patients with incident hypertension with and without comorbidities., Methods: Hypertensive patients newly diagnosed between April 1, 1998 and March 31, 2009 were identified using Alberta administrative databases. Three comorbidity subgroups were defined: (1) none, (2) vascular risk related, and (3) unrelated. The number of PCP visits was calculated using zero-inflation Poisson regression, with time trends compared using the χ(2) test. A Cox model was used to assess the association between PCP use and clinical outcomes., Results: Of 456,263 newly diagnosed hypertensive patients (mean age, 57.6 years; 50.6% men; 62.5% no comorbidity), 88% had seen a PCP in the year before diagnosis, and 94% had seen a PCP in the year after being diagnosed. Compared with before diagnosis, the mean number of PCP visits increased after diagnosis (none, 3.95 vs 6.15; vascular risk related, 6.45 vs 7.99; and unrelated, 6.76 vs 8.24). Over the study period, the frequency of PCP visits before diagnosis was constant, and there was a statistically significant decline in the adjusted mean number of visits after diagnosis. Those with higher PCP use were less likely to die but more likely to be hospitalized regardless of comorbidity., Conclusions: The frequency of PCP visits was high before and after diagnosis. Increased PCP use was associated with a lower risk of death; however, it does increase the costs of caring for patients with hypertension. Therefore, future studies are necessary to determine the optimal level required to achieve cost-effective use of PCP resources., (Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Objectives: With an increase and diversity in ethnic populations in Westernized countries, understanding the differences in levels of knowledge surrounding hypertension is important in planning appropriate prevention strategies. The purpose of our study was to assess levels of hypertension knowledge in Chinese, Indian and White populations in a large metropolitan Canadian city., Design: A telephone survey was conducted in English, Chinese (Cantonese and Mandarin) and Indian languages (Hindi, Punjabi and Urdu). Hypertension knowledge was assessed through a 10-item validated instrument; respondents received 1 point for each correct answer. Logistic regression was used to test differences in hypertension knowledge among these three populations., Results: Survey response rates were 68.7% (301) for Chinese, 61.3% (248) for Indian and 69.7% (254) for White populations. The average hypertension knowledge score for Chinese respondents was 7.23 out of 10, 7.11 for Indian respondents and 7.28 for White respondents. Compared to White respondents, Chinese respondents were less likely than White respondents to know high blood pressure can cause heart attacks (adjusted odds ratio [aOR]: .43, 95% confidence interval [CI]: .19-.96] and Indian respondents were less likely to know losing weight usually decreases blood pressure (aOR: .38, 95% CI: .21-.68)., Conclusions: Hypertension knowledge levels among these three ethnic/racial populations were similar and relatively high and varied by content. Low levels of knowledge for Chinese and Indian ethnic populations were on hypertension risk factors, long-term consequences of hypertension and anti-hypertensive medication adherence. Specifically, females, recent immigrants to Canada and Chinese seniors were identified as sub-groups who should be targeted for hypertension knowledge promotion.

Background: Hospitalizations for ambulatory care sensitive conditions (ACSC) represent an indirect measure of access and quality of community care. This study explored hospitalization rates for 1 ACSC, uncomplicated hypertension, and the factors associated with hospitalization., Methods: A cohort of patients with incident hypertension, and their covariates, was defined using validated case definitions applied to International Classification of Disease administrative health data in 4 Canadian provinces between fiscal years 1997 and 2004. We applied the Canadian Institute for Health Information's case definition to detect all patients who had an ACSC hospitalization for uncomplicated hypertension. We employed logistic regression to assess factors associated with an ACSC hospitalization for uncomplicated hypertension., Results: The overall rate of hospitalizations for uncomplicated hypertension in the 4 provinces was 3.7 per 1000 hypertensive patients. The risk-adjusted rate was lowest among those in an urban setting (2.6 per 1000; 95% confidence interval [CI], 2.3-2.7), the highest income quintile (3.4 per 1000; 95% CI, 2.8-4.2), and those with no comorbidities (3.6 per 1000; 95% CI, 3.2-3.9). Overall, Newfoundland had the highest adjusted rate (5.7 per 1000; 95% CI, 4.9-6.7), and British Columbia had the lowest (3.7 per 1000; 95% CI, 3.4-4.2). The adjusted rate declined from 5.9 per 1000 in 1997 to 3.7 per 1000 in 2004., Conclusions: We found that the rate of hospitalizations for uncomplicated hypertension has decreased over time, which might reflect improvements in community care. Geographic variations in the rate of hospitalizations indicate disparity among the provinces and those residing in rural regions., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Objective: To compare ethnic and sex difference in the incidence of newly diagnosed hypertension, and subsequent risk of cardiovascular disease outcomes among South Asian, Chinese and white patients., Methods: We identified patients with newly diagnosed hypertension aged ≥20 years. Patients were followed for 1-9 years for all-cause mortality and cardiovascular disease with myocardial infarction, heart failure and stroke. Cox proportional hazard models stratified by sex and adjusted for age, median income and co-morbid conditions, were constructed to determine the independent association between ethnicity and the development of the combined cardiovascular endpoint as well as death., Results: There were 39 175 South Asian (49.4% men, 34.4% age ≥65), 49 892 Chinese (48.1% men, 36.7% age ≥65) and 841 277 white (47.9% men, 38.8% age ≥65) patients with newly diagnosed hypertension. Age and sex adjusted incidence of hypertension was highest in South Asian patients and lowest in Chinese patients. Compared with white patients, South Asian and Chinese patients had a lower mortality (adjusted HR (aHR) 0.91 and 0.66) and risk of cardiovascular disease outcomes (aHR 0.94 and 0.49). Compared to men, women had significantly lower mortality (aHR: 0.83 for Chinese, 0.78 for South Asian and 0.77 for white) and cardiovascular disease outcomes (0.72 for Chinese, 0.63 for South Asian and 0.65 for white)., Conclusions: South Asian patients had higher rates of hypertension compared to the other ethnic groups. South Asian and Chinese patients had a lower risk of death and developing cardiovascular outcomes compared to whites. Women with hypertension have a better prognosis than men regardless of ethnicity.

Background: This population-based study assessed rates of all-cause mortality, myocardial infarction, heart failure, and stroke for up to 12 years of follow-up in 3.5 million Canadian adults newly diagnosed with hypertension., Methods: Hypertension cohort, outcomes, and covariates were defined using validated case definitions applied to inpatient and outpatient administrative health databases. Factors associated with each outcome were identified using Cox proportional hazards models., Results: Of 3,531,089 adults newly diagnosed with hypertension and without a previous history of cardiovascular disease, 29.4% were younger than 50 years of age; 48.2% were male, and 17.2% resided in a rural area. Over a median follow-up length of 6.1 years, the crude all-cause mortality rate was 22.4 per 1000 person-years. The incidence of hospitalized myocardial infarction (8.4 per 1000 person-years) and hospitalized heart failure (8.5 per 1000 person-years) was higher than stroke (6.9 per 1000 person-years). The incidence rate for any cardiovascular hospitalization was 19.3 per 1000 person-years. Older age, male sex, lower income, rural residence, and a higher number of Charlson comorbidities were each independently associated with a higher risk of mortality and incident cardiovascular disease hospitalizations., Conclusions: In a nationally-representative incident cohort of hypertensive adults we have demonstrated higher mortality rates and poorer outcomes for the elderly, males, and those living in rural or low income locations. Innovative approaches to the provision of care for these high-risk individuals will lead to improved patient outcomes., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Blood pressure surveillance, monitoring, and evaluation of programs to prevent and control hypertension are critical because increased blood pressure is a leading risk for premature death and disability. Since 2003, the Hypertension Outcomes Research Task Force has existed in Canada, with members who assist in the development and revision of surveys and conduct analyses that help guide hypertension programs. Although the Task Force has tracked a 5-fold increase in the control of hypertension (from 13% in 1985-1992 to 65% in 2007-2009), surveillance data also indicate that many "care gaps" remain. Fifty-four percent of people with diabetes and 34% of those without diabetes have blood pressure readings greater than their target. Treatment rates are high in those who are diagnosed (95%), but 17% of people with hypertension remain undiagnosed. Younger men (more so than women) are too often unaware of having hypertension. Although they are more likely to be aware of their diagnosis, older women are 2 times more likely to have uncontrolled hypertension than men; systolic blood pressure is high in over 80% of those with uncontrolled blood pressure (90% in women); and often people with hypertension are not provided comprehensive advice on healthy behaviours, or assisted in developing plans to control their blood pressure. Many current surveys do not have adequate statistical power to assess vulnerable populations; surveys of Aboriginal populations do not usually assess blood pressure, such that the burden of hypertension in these high risk populations cannot be assessed., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

We conducted this study to determine levels and correlates of hypertension knowledge among rural Chinese adults, and to assess the association between knowledge levels and salty food consumption among hypertensive and non-hypertensive populations. This face-to-face cross sectional survey included 665 hypertensive and 854 non-hypertensive respondents in the rural areas of Heilongjiang province, China. Hypertension knowledge was assessed through a 10-item test; respondents received 10 points for each correct answer. Among respondents, the average hypertension knowledge score was 26 out of a maximum of 100 points for hypertensive and 20 for non-hypertensive respondents. Hypertension knowledge was associated with marital status, education, health status, periodically reading books, newspapers or other materials, history of blood pressure measurement, and attending hypertension educational sessions. Hypertension knowledge is extremely low in rural areas of China. Hypertension education programs should focus on marginal populations, such as individuals who are not married or illiterate to enhance their knowledge levels. Focusing on educational and literacy levels in conjunction with health education is important given illiteracy is still a prominent issue for the Chinese rural population.

Background: Hypertension is a leading risk factor for cardiovascular diseases. Our objectives were to examine the prevalence and incidence of diagnosed hypertension in Canada and compare mortality among people with and without diagnosed hypertension., Methods: We obtained data from linked health administrative databases from each province and territory for adults aged 20 years and older. We used a validated case definition to identify people with hypertension diagnosed between 1998/99 and 2007/08. We excluded pregnant women from the analysis., Results: This retrospective population-based study included more than 26 million people. In 2007/08, about 6 million adults (23.0%) were living with diagnosed hypertension and about 418,000 had a new diagnosis. The age-standardized prevalence increased significantly from 12.5% in 1998/99 to 19.6% in 2007/08, and the incidence decreased from 2.7 to 2.4 per 100. Among people aged 60 years and older, the prevalence was higher among women than among men, as was the incidence among people aged 75 years and older. The prevalence and incidence were highest in the Atlantic region. For all age groups, all-cause mortality was higher among adults with diagnosed hypertension than among those without diagnosed hypertension., Interpretation: The overall prevalence of diagnosed hypertension in Canada from 1998 to 2008 was high and increasing, whereas the incidence declined during the same period. These findings highlight the need to continue monitoring the effectiveness of efforts for managing hypertension and to enhance public health programs aimed at preventing hypertension.

Background: Little is known regarding potential differences in antihypertensive prescribing practices at a Canadian provincial level. Our objective was to determine provincial differences in the use of antihypertensive drug therapy in Canada., Methods: Using longitudinal drug data (IMS CompuScript database; IMS Health Canada), we examined the increase in number of prescriptions dispensed for all antihypertensive agents for each province over an 11-year period (1996-2006)., Results: Over the 11-year study period, antihypertensive prescriptions increased by 106.2% for single-drug therapy (from 35.8% in Prince Edward Island and Newfoundland to 167.2% in British Columbia) and by 112.8% (from 22.0% in New Brunswick to 216.0% in Québec) for combination-drug therapy. Among drug classifications, angiotensin receptor blockers had the largest increase for single-drug therapy and angiotensin-converting enzyme inhibitors-diuretics for combination-drug therapy. There were marked provincial differences in the increase in total antihypertensive therapy, ranging from British Columbia, with an increase of 262%, to Prince Edward Island and Newfoundland, where the increase was 134%., Conclusion: Large increases in antihypertensive prescriptions occurred in all provinces of Canada, but the provinces varied substantially in the increase in total and drug-specific classes of antihypertensive drugs. The basis for provincial differences in antihypertensive prescriptions remains unknown and is likely multifactorial but may relate in part to initial provincial variations in diagnosis, treatment, and control of hypertension, as well as individual provincial drug policies., (Copyright © 2011 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

We validated the accuracy of case definitions for hypertension derived from administrative data across time periods (year 2001 versus 2004) and geographic regions using physician charts. Physician charts were randomly selected in rural and urban areas from Alberta and British Columbia, Canada, during years 2001 and 2004. Physician charts were linked with administrative data through unique personal health number. We reviewed charts of approximately 50 randomly selected patients >35 years of age from each clinic within 48 urban and 16 rural family physician clinics to identify physician diagnoses of hypertension during the years 2001 and 2004. The validity indices were estimated for diagnosed hypertension using 3 years of administrative data for the 8 case-definition combinations. Of the 3,362 patient charts reviewed, the prevalence of hypertension ranged from 18.8% to 33.3%, depending on the year and region studied. The administrative data hypertension definition of "2 claims within 2 years or 1 hospitalization" had the highest validity relative to the other definitions evaluated (sensitivity 75%, specificity 94%, positive predictive value 81%, negative predictive value 92%, and kappa 0.71). After adjustment for age, sex, and comorbid conditions, the sensitivities between regions, years, and provinces were not significantly different, but the positive predictive value varied slightly across geographic regions. These results provide evidence that administrative data can be used as a relatively valid source of data to define cases of hypertension for surveillance and research purposes.

The aim of this study was to investigate the association of antecedent hypertension with adverse cardiovascular outcomes after myocardial infarction. A search of Medline and EMBASE was supplemented by manual searches of the bibliographies of key retrieved reports. The studies were included if they reported antecedent hypertension as a risk factor for adverse outcomes (death, stroke, congestive heart failure, recurrent myocardial infarction) in survivors of myocardial infarctions. Relative risks (RRs) were pooled using a random-effects model, and the robustness of the pooled RRs was evaluated in sensitivity analyses. Cumulative meta-analysis, by chronologic year of study beginning, was also performed. The search yielded 17 studies (n = 56,748 participants) that reported antecedent hypertension with adverse outcomes for survivors of myocardial infarctions. Randomized clinical trials (n = 8) were pooled separately from cohort studies (n = 9). For randomized clinical trials, the pooled RRs were 1.19 (95% confidence interval [CI] 1.13 to 1.26) for all-cause mortality and 1.29 (95% CI 1.09 to 1.53) for cardiovascular disease mortality. For cohort studies, the pooled RRs were 1.46 (95% CI 1.34 to 1.61) for all-cause mortality and 1.54 (95% CI 1.22 to 1.93) for cardiovascular disease mortality. Antecedent hypertension was also consistently associated with an increased risk for stroke, congestive heart failure, and recurrent myocardial infarction. Pooled estimates were robust in sensitivity analysis. In conclusion, antecedent hypertension was associated with adverse outcomes for survivors of myocardial infarctions, the association of antecedent hypertension with all-cause mortality outcomes decreased over time, and this decreased association reflects improved treatment and management of hypertension in more recent years.

Background: In 1999, the Canadian Hypertension Education Program (CHEP) was launched to develop and implement evidence-based hypertension guidelines., Objectives: To determine temporal trends in antihypertensive drug prescribing and physician visits for hypertension in Canada, and correlate these trends with CHEP recommendations., Methods: Longitudinal drug data (Intercontinental Medical Statistics [IMS] CompuScript database; IMS Health Canada) were used to examine prescriptions over an 11-year period (1996 to 2006) for five major cardiovascular drug classes. The IMS Canadian Disease and Therapeutic Index database was used to determine trends in physician office visits for hypertension., Results: Prescriptions for antihypertensive agents increased significantly over the 11-year period (4054% for angiotensin receptor blockers, 127% for thiazide diuretics, 108% for angiotensin-converting enzyme inhibitors, 87% for beta-blockers and 55% for calcium channel blockers). Time series analyses demonstrated increases in the growth rate for all drug classes, with the greatest annual change in prescriptions occurring during the 1999 to 2002 time period (except in angiotensin receptor blockers). An increase in prescriptions for fixed-dose combination products occurred, which was temporally related to the change in CHEP recommendations encouraging their use in 2001. The proportion of physician office visits for hypertension increased significantly from 4.9% in 1995 to 6.8% in 2005 (P<0.001)., Conclusions: The largest increase in antihypertensive drug prescribing occurred in the period immediately following implementation of CHEP (1999 to 2002). Although prescribing rates are still increasing, the rate of change has decreased, suggesting that the treatment market for hypertension may be becoming saturated. The impact of these changes on blood pressure control and clinical outcomes remains to be determined.

Background: Many Canadians known to have hypertension remain untreated. To aid in the development of specific programs to improve hypertension management, the present report characterizes Canadians who indicated that they had hypertension but were not taking antihypertensive drug therapy., Methods: The 2005 Canadian Community Health Survey (cycle 3.1) was used to estimate the proportion of Canadians 20 years of age and older who reported having high blood pressure or ever being diagnosed with high blood pressure. Sociodemographic characteristics, reported health, lifestyle factors and health care resource use of those who reported taking or not taking high blood pressure medication in the previous month were described and compared., Results: Over one-half of hypertensive respondents 20 to 39 years of age reported no antihypertensive treatment compared with 17% and 5% among those 40 to 59 years and 60 years of age and older, respectively. In most age groups, several factors were associated with the absence of pharmacotherapy (eg, male sex, fewer health care professional consultations, perceived excellent health status and most markers of lower cardiovascular risk, with the exception of daily smoking). The proportion of young hypertensive Canadians not receiving pharmacotherapy remained consistent, regardless of the presence of cardiovascular risk factors., Conclusions: Many hypertensive Canadians, particularly those who are younger than 60 years of age, are not taking antihypertensive drug therapy despite having one or more cardiovascular risks. The increased risk of no drug therapy among smokers warrants special attention.

This study examined the coding validity of hypertension, diabetes, obesity and depression related to the presence of their co-existing conditions, death status and the number of diagnosis codes in hospital discharge abstract database. We randomly selected 4007 discharge abstract database records from four teaching hospitals in Alberta, Canada and reviewed their charts to extract 31 conditions listed in Charlson and Elixhauser comorbidity indices. Conditions associated with the four study conditions were identified through multivariable logistic regression. Coding validity (i.e. sensitivity, positive predictive value) of the four conditions was related to the presence of their associated conditions. Sensitivity increased with increasing number of diagnosis code. Impact of death on coding validity is minimal. Coding validity of conditions is closely related to its clinical importance and complexity of patients’ case mix. We recommend mandatory coding of certain secondary diagnosis to meet the need of health research based on administrative health data. [ABSTRACT FROM AUTHOR]

Background: Vascular dementia (VaD) is the second most common form of dementia. However, there were mixed evidences about the association between blood pressure (BP) and risk of VaD in midlife and late life and limited evidence on the association between pulse pressure and VaD.Methods: This is a population-based observational study. 265,897 individuals with at least one BP measurement between the ages of 60 to 65 years and 211,116 individuals with at least one BP measurement between the ages of 70 to 75 years were extracted from The Health Improvement Network in United Kingdom. Blood pressures were categorized into four groups: normal, prehypertension, stage 1 hypertension, and stage 2 hypertension. Cases of VaD were identified from the recorded clinical diagnoses. Multivariable survival analysis was used to adjust other confounders and competing risk of death. All the analysis were stratified based on antihypertensive drug use status. Multiple imputation was used to fill in missing values.Results: After accounting for the competing risk of death and adjustment for potential confounders, there was an association between higher BP levels in the age 60-65 cohort with the risk of developing VaD (hazard ratio [HR] 1.53 (95% confidence interval: 1.04, 2.25) for prehypertension, 1.90 (1.30, 2.78) for stage 1 hypertension, and 2.19 (1.48, 3.26) for stage 2 hypertension) in the untreated group. There was no statistically significant association between BP levels and VaD in the treated group in the age 60-65 cohort and age 70-75 cohort. Analysis on Pulse Pressure (PP) stratified by blood pressure level showed that PP was not independently associated with VaD.Conclusion: High BP between the ages of 60 to 65 years is a significant risk for VaD in late midlife. Greater efforts should be placed on early diagnosis of hypertension and tight control of BP for hypertensive patients for the prevention of VaD. [ABSTRACT FROM AUTHOR]

Background: Surveillance using coded administrative health data has shown that the prevalence of hypertension and diabetes in Canada increased substantially between 1998 to 2008. These findings require an assumption that the validity of hypertension and diabetes coding is stable over time. We tested this assumption by examining temporal trends in the validity of coding for hypertension and diabetes in the Canadian hospital Discharge Abstract Database. Methods: We used the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) database, a clinical registry, as the reference standard to evaluate the validity of the Discharge Abstract Database in recording hypertension and diabetes in Alberta. The APPROACH database contains data for all Alberta residents who have undergone cardiac catheterization and includes prospective ascertainment of comorbid conditions before each procedure. We linked patient data between the 2 databases for 2002 to 2013 using patient provincial health number. Temporal trends in sensitivity, specificity, positive predictive value, negative predictive value and Cohen - were calculated for both hypertension and diabetes in the Discharge Abstract Database. Results: We matched 63 483 patients between the APPROACH database and the Discharge Abstract Database. The validity of the Discharge Abstract Database for hypertension and diabetes remained mostly consistent over time. Between 2002 and 2013, sensitivity, specificity, positive predictive value and negative predictive value ranged from 66% to 87% for hypertension and from 81% to 98% for diabetes; the corresponding scores ranged from 0.50 to 0.62 and from 0.80 to 0.89. No significant differences in the validity of coding were found across age, sex or hospital location subgroups. Interpretation: The validity of coding for hypertension and diabetes in the Discharge Abstract Database remained fairly consistent between 2002 and 2013. Our findings support the use of the Discharge Abstract Database for hypertension and diabetes surveillance in hospital settings. [ABSTRACT FROM AUTHOR]

Background Electronic medical records (EMR) can be a cost-effective source for hypertension surveillance. However, diagnosis of hypertension in EMR is commonly under-coded and warrants the needs to review blood pressure and antihypertensive drugs for hypertension case identification. Methods We included all the patients actively registered in The Health Improvement Network (THIN) database, UK, on 31 December 2011. Three case definitions using diagnosis code, antihypertensive drug prescriptions and abnormal blood pressure, respectively, were used to identify hypertension patients. We compared the prevalence and treatment rate of hypertension in THIN with results from Health Survey for England (HSE) in 2011. Results Compared with prevalence reported by HSE (29.7%), the use of diagnosis code alone (14.0%) underestimated hypertension prevalence. The use of any of the definitions (38.4%) or combination of antihypertensive drug prescriptions and abnormal blood pressure (38.4%) had higher prevalence than HSE. The use of diagnosis code or two abnormal blood pressure records with a 2-year period (31.1%) had similar prevalence and treatment rate of hypertension with HSE. Conclusions Different definitions should be used for different study purposes. The definition of 'diagnosis code or two abnormal blood pressure records with a 2-year period' could be used for hypertension surveillance in THIN. [ABSTRACT FROM AUTHOR]

Background: Hypertension is a leading risk factor for cardiovascular diseases. Our objectives were to examine the prevalence and incidence of diagnosed hypertension in Canada and compare mortality among people with and without diagnosed hypertension. Methods: We obtained data from linked health administrative databases from each province and territory for adults aged 20 years and older. We used a validated case definition to identify people with hypertension diagnosed between 1998/99 and 2007/08. We excluded pregnant women from the analysis. Results: This retrospective population-based study included more than 26 million people. In 2007/08, about 6 million adults (23.0%) were living with diagnosed hypertension and about 418 000 had a new diagnosis. The agestandardized prevalence increased significantly from 12.5% in 1998/99 to 19.6% in 2007/08, and the incidence decreased from 2.7 to 2.4 per 100. Among people aged 60 years and older, the prevalence was higher among women than among men, as was the incidence among people aged 75 years and older. The prevalence and incidence were highest in the Atlantic region. For all age groups, allcause mortality was higher among adults with diagnosed hypertension than among those without diagnosed hypertension. Interpretation: The overall prevalence of diagnosed hypertension in Canada from 1998 to 2008 was high and increasing, whereas the incidence declined during the same period. These findings highlight the need to continue monitoring the effectiveness of efforts for managing hypertension and to enhance public health programs aimed at preventing hypertension. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to determine whether South Asian patients with diabetes have a worse prognosis following hospitalization for acute myocardial infarction (AMI) compared with their White counterparts. We measured the risk of developing a composite cardiovascular outcome of recurrent AMI, congestive heart failure (CHF) requiring hospitalization, or death, in these two groups. Methods: Using hospital administrative data, we performed a retrospective cohort study of 41,615 patients with an incident AMI in British Columbia and the Calgary Health Region between April 1, 1995, and March 31, 2002. South Asian ethnicity was determined using validated surname analysis. Baseline demographic characteristics and comorbidities were included in Cox proportional hazard models to compare time to reaching the composite outcome and its individual components. Results: Among the AMI cohort, 29.7% of South Asian patients and 17.6% of White patients were identified as having diabetes (n = 7416). There was no significant difference in risk of developing the composite cardiovascular outcome (Hazard Ratio = 0.90, 95% CI = 0.80-1.01). However, South Asian patients had significantly lower mortality at long term follow-up (HR = 0.62, 95% CI = 0.51-0.74) compared to their White counterparts. Conclusions: Following hospitalization for AMI, South Asian patients with diabetes do not have a significantly different long term risk of a composite cardiovascular outcome compared to White patients with diabetes. While previous research has suggested worse cardiovascular outcomes in the South Asian population, we found lower long-term mortality among South Asians with diabetes following AMI. [ABSTRACT FROM AUTHOR]