Effects of the COVID-19 Pandemic on Primary Health Care for Chronic Conditions in Canada: Protocol for a Retrospective Pre-Post Study Using National Practice-Based Research Network Data.

BACKGROUND: Since the COVID-19 pandemic began, there have been concerns that interruptions to the health care system may have led to changes in primary care, especially for care of chronic conditions such as diabetes and heart failure. Such changes may have longer term implications for population health. OBJECTIVE: This study aims to describe the impacts of the COVID-19 pandemic on indicators of primary care access, comprehensiveness, and appropriateness among adult patients, as well as on specific indictors of chronic conditions. Additionally, this study aims to determine whether any identified changes were associated with patient sociodemographic characteristics and multimorbidity. METHODS: This is a retrospective, single-arm, pre-post study using Canadian Primary Care Sentinel Surveillance Network (CPCSSN) data. CPCSSN is a research network supported by a primary care electronic medical record database, comprising over 1500 physicians and nearly 2 million patients. We are examining changes in care (eg, frequency of contacts, laboratory tests and investigations, referrals, medications prescribed, etc) among adults. We will also examine indicators specific to evidence-based recommendations for care in patients with diabetes and those with heart failure. We will compare rates of outcomes during key periods of the pandemic between March 13, 2020, and December 31, 2022, with equal time periods before the pandemic. Differences will be examined among specific subgroups of adults, including by decade of age, number of comorbidities, and socioeconomic status. Regression models appropriate to outcome distributions will be used to estimate changes, adjusting for potential confounders. This analysis is part of a mixed-methods study with a qualitative component investigating how patients with diabetes with or without concurrent heart failure perceived the impact of the pandemic on access to primary care and health care-related decisions. This study was approved by the Hamilton Integrated Research Ethics Board (14782-C). RESULTS: The start date of this study was October 5, 2022, and the prospective end date is January 31, 2024. As of May 2023, the study cohort (n=875,934) is defined, data cleaning is complete, and exploratory analyses have begun. Extended analyses using 2022 data are planned once the new data becomes available. We will disseminate results through peer-reviewed publications and academic conference, as well as creating evidence briefs, infographics, and a video for policy maker and patient audiences. CONCLUSIONS: This study will investigate whether the COVID-19 pandemic has resulted in changes in the provision of primary care in Canada and whether these potential changes have led to gaps in care. This study will also identify patient-level characteristics associated with changes in care patterns across the COVID-19 pandemic. Indicators specific to chronic conditions, namely diabetes and heart failure, will also be explored to determine whether there were changes in care of these conditions. TRIAL REGISTRATION: ClinicalTrials.gov NCT05813652; https://clinicaltrials.gov/ct2/show/NCT05813652. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/49131.

Integrating User Preferences for Asthma Tools and Clinical Guidelines Into Primary Care Electronic Medical Records: Mixed Methods Study.

BACKGROUND: Asthma is a chronic respiratory disease that poses a substantial burden on individuals and the health care system. Despite published national guidelines for the diagnosis and management of asthma, considerable care gaps exist. Suboptimal adherence to asthma diagnosis and management guidelines contributes to poor patient outcomes. The integration of electronic tools (eTools) into electronic medical records (EMRs) represents a knowledge translation opportunity to support best practices. OBJECTIVE: The purpose of this study was to determine how best to integrate evidence-based asthma eTools into primary care EMRs across Ontario and Canada to improve adherence to guidelines as well as measure and monitor performance. METHODS: In total, 2 focus groups comprising physicians and allied health professionals who were considered experts in primary care, asthma, and EMRs were convened. One focus group also included a patient participant. Focus groups used a semistructured discussion-based format to consider the optimal methods for integrating asthma eTools into EMRs. Discussions were held on the web via Microsoft Teams (Microsoft Corp). The first focus group discussed integrating asthma indicators into EMRs using eTools, and participants completed a questionnaire evaluating the clarity, relevance, and feasibility of collecting asthma performance indicator data at the point of care. The second focus group addressed how to incorporate eTools for asthma into a primary care setting and included a questionnaire evaluating the perceived utility of various eTools. Focus group discussions were recorded and analyzed using thematic qualitative analysis. The responses to focus group questionnaires were assessed using descriptive quantitative analysis. RESULTS: Qualitative analysis of the 2 focus group discussions revealed 7 key themes: designing outcome-oriented tools, gaining stakeholder trust, facilitating open lines of communication, prioritizing the end user, striving for efficiency, ensuring adaptability, and developing within existing workflows. In addition, 24 asthma indicators were rated according to clarity, relevance, feasibility, and overall usefulness. In total, 5 asthma performance indicators were identified as the most relevant. These included smoking cessation support, monitoring using objective measures, the number of emergency department visits and hospitalizations, assessment of asthma control, and presence of an asthma action plan. The eTool questionnaire responses revealed that the Asthma Action Plan Wizard and Electronic Asthma Quality of Life Questionnaire were perceived to be the most useful in primary care. CONCLUSIONS: Primary care physicians, allied health professionals, and patients consider that eTools for asthma care present a unique opportunity to improve adherence to best-practice guidelines in primary care and collect performance indicators. The strategies and themes identified in this study can be leveraged to overcome barriers associated with asthma eTool integration into primary care EMRs. The most beneficial indicators and eTools, along with the key themes identified, will guide future asthma eTool implementation.

A cross-sectional study evaluating cardiovascular risk and statin prescribing in the Canadian Primary Care Sentinel Surveillance Network database.

BACKGROUND: Cardiovascular disease (CVD) is a major cause of morbidity and mortality in Canada. Assessment and management of CVD risk is essential in reducing disease burden. This includes both clinical risk factors and socioeconomic factors, though few studies report on socioeconomic status in relation to CVD risk and treatment. The primary objective of this study was to estimate the cardiovascular risk of patients attending primary care practices across Canada; secondly, to evaluate concordance with care indicators suggested by current clinical practice guidelines for statin prescribing according to patients' cardiovascular risk and socioeconomic status. METHODS: This cross-sectional observational study used the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) database, which is comprised of clinical data from primary care electronic medical records. Patients aged 35-75y with at least one visit to their primary care provider between 2012 and 2016 were included. Patients were assigned to a CVD risk category (high, medium, low) and a deprivation quintile was calculated for those with full postal code available. Descriptive analyses were used to determine the proportion of patients in each risk category. Logistic regression was used to evaluate the consistency of statin prescribing according to national clinical guidelines by risk category and deprivation quintile. RESULTS: A total of 324,526 patients were included. Of those, 116,947 (36%) of patients were assigned to a high CVD risk category, primarily older adults, males, and those with co-morbidities. There were statistically significant differences between least (quintile 1) and most (quintile 5) deprived socioeconomic quintiles, with those at high CVD risk disproportionately in Q5 (odds ratio 1.4). Overall, 48% of high-risk patients had at least one statin prescription in their record. Patients in the lower socioeconomic groups had a higher risk of statin treatment which deviated from clinical guidelines. CONCLUSIONS: Primary care patients who are at high CVD risk are more often male, older, have more co-morbidities and be assigned to more deprived SES quintiles, compared to those at low CVD risk. Additionally, patients who experience more challenging socioeconomic situations may be less likely to receive CVD treatment that is consistent with care guidelines.

Detecting Patients With Nonvalvular Atrial Fibrillation and Atrial Flutter in the Canadian Primary Care Sentinel Surveillance Network: First Steps.

BACKGROUND: A recent feasibility assessment of quality indicators for nonvalvular atrial fibrillation/atrial flutter (NVAF/AFL) identified the Canadian Primary Care Sentinel Surveillance Network, a national outpatient electronic medical record (EMR) system, as a data source for measurement. As a first step, we adapted and validated an existing EMR case definition. METHODS: A diagnosis of NVAF/AFL was defined using International Classification of Disease, 9th Revision, Clinical Modification codes (427.3) in either the physician billing, encounter diagnosis, or health condition fields. We identified all presumed cases in a single clinical site with the algorithm and selected a random sample of those who were presumed NVAF/AFL negative with the same algorithm. A chart audit diagnosis of "definite" NVAF/AFL was confirmed by electrocardiogram and nonvalvular diagnosis confirmed after echocardiogram, attending physician, or specialist letter review. To demonstrate face validity, clinical characteristics were compared for patients with and without NVAF/AFL. RESULTS: The case definition identified a possible 184 patients with and 184 without NVAF/AFL. The case validation resulted in a sensitivity of 100% (95% confidence interval [CI], 100-100), specificity of 84.3% (95% CI, 78.8-89.9), and positive and negative predictive value of 74.7% (95% CI, 66.4-83.2) and 100% (95% CI 100-100), respectively. Patients with NVAF/AFL were older (63 vs 42 years) and had a higher proportion of cardiovascular comorbidities and relevant medications. CONCLUSIONS: We think it is possible that with further validation work, NVAF/AFL can be accurately identified using this large pan-Canadian EMR system and used as a future tool to measure quality of care in the outpatient setting.

CONTEXTE: Dans le cadre d'une étude récente visant à déterminer s'il est possible d'utiliser des indicateurs de qualité pour évaluer les soins prodigués en cas de fibrillation auriculaire (FA) non valvulaire/flutter auriculaire, le Réseau canadien de surveillance sentinelle en soins primaires, un système national regroupant des données provenant des dossiers médicaux électroniques (DME) de patients vus en contexte de soins ambulatoires, a été retenu comme source de données pour une telle évaluation. Dans un premier temps, nous avons adapté et validé une définition de cas existante dans les DME. MÉTHODOLOGIE: On considérait qu'il y avait diagnostic de FA non valvulaire/flutter auriculaire si le code de la Classification internationale des maladies (9e révision, Modification clinique) correspondant (code 427.3) figurait dans un des champs de facturation des actes médicaux, des diagnostics de consultation ou des problèmes de santé du DME. Nous avons relevé tous les cas de FA non valvulaire/flutter auriculaire présumés d'une même clinique à l'aide de l'algorithme établi et constitué un échantillon aléatoire de patients qui, selon le même algorithme, ne présentaient pas de FA non valvulaire/flutter auriculaire. On a ensuite vérifié les dossiers pour confirmer le diagnostic; le cas de FA non valvulaire/flutter auriculaire était « certain ¼ si le dossier comprenait un électrocardiogramme positif et un diagnostic confirmé par échocardiographie, ou une note du médecin traitant ou d'un spécialiste confirmant le diagnostic. Pour démontrer la validité apparente de l'algorithme, les caractéristiques cliniques des patients atteints de FA non valvulaire/flutter auriculaire ont été comparées à celles des patients sans FA non valvulaire/flutter auriculaire. RÉSULTATS: La définition de cas a permis de repérer 184 patients ayant possiblement une FA non valvulaire/flutter auriculaire, et 184 autres patients sans FA non valvulaire/flutter auriculaire. À l'issue de la validation, la sensibilité de la définition de cas s'établissait à 100 % (intervalle de confiance [IC] à 95 % : 100 à 100), sa spécificité, à 84,3 % (IC à 95 % : 78,8 à 89,9), et ses valeurs prédictives positive et négative, à respectivement 74,7 % (IC à 95 % : 66,4 à 83,2) et 100 % (IC à 95 % : 100 à 100). Les patients atteints de FA non valvulaire/flutter auriculaire étaient plus âgés (63 vs 42 ans) et recevaient un traitement pour des affections cardiovasculaires concomitantes dans une plus forte proportion. CONCLUSIONS: Nous croyons qu'en approfondissant les travaux de validation, il serait possible de repérer avec précision les cas de FA non valvulaire/flutter auriculaire à partir des données de ce système pancanadien de surveillance des DME et de les utiliser pour évaluer la qualité des soins aux patients vus en contexte ambulatoire.

Data quality in healthcare: A report of practical experience with the Canadian Primary Care Sentinel Surveillance Network data.

Data quality (DQ) is the degree to which a given dataset meets a user's requirements. In the primary healthcare setting, poor quality data can lead to poor patient care, negatively affect the validity and reproducibility of research results and limit the value that such data may have for public health surveillance. To extract reliable and useful information from a large quantity of data and to make more effective and informed decisions, data should be as clean and free of errors as possible. Moreover, because DQ is defined within the context of different user requirements that often change, DQ should be considered to be an emergent construct. As such, we cannot expect that a sufficient level of DQ will last forever. Therefore, the quality of clinical data should be constantly assessed and reassessed in an iterative fashion to ensure that appropriate levels of quality are sustained in an acceptable and transparent manner. This document is based on our hands-on experiences dealing with DQ improvement for the Canadian Primary Care Sentinel Surveillance Network database. The DQ dimensions that are discussed here are accuracy and precision, completeness and comprehensiveness, consistency, timeliness, uniqueness, data cleaning and coherence.

Validation of an EMR algorithm to measure the prevalence of ADHD in the Canadian Primary Care Sentinel Surveillance Network (CPCSSN).

BACKGROUND: Building and validating electronic algorithms to identify patients with specific disease profiles using health data is becoming increasingly important to disease surveillance and population health management. The aim of this study was to develop and validate an algorithm to find patients with ADHD diagnoses within primary care electronic medical records (EMR); and then use the algorithm to describe the epidemiology of ADHD from 2008 to 2015 in a Canadian Primary care sample. METHODS: This was a cross sectional time series that used data from the Canadian Primary Care Sentinel Surveillance Network (CPCSSN), a repository of primary care EMR data. A sample of electronic patient charts from one local clinic were manually reviewed to determine the positive predictive value (PPV) and negative predictive value (NPV) of an ADHD case-finding algorithm. In each study year a practice population was determined, and the algorithm was used to measure an observed prevalence of ADHD. The observed prevalence was adjusted for misclassification, as measured by the validity indices, to obtain an estimate of the true prevalence. Estimates were calculated by age group (4-17 year olds, 18 to 34 year olds, and 35 to 64 year olds) and gender, and compared over time. RESULTS: The EMR algorithm had a PPV of 98.0% (95% CI [92.5, 99.5]) and an NPV of 95.0% (95% CI [92.9, 98.6]). After adjusting for misclassification, it was determined that the prevalence of patients with a clinical diagnosis of ADHD has risen in all age groups between 2008 and 2015, most notably in children and young adults (6.92, 95% CI [5.62, 8.39] to 8.57, 95% CI [7.32, 10.00]; 5.73, 95% CI [4.40, 7.23] to 7.33, 95% CI [6.04, 8.78], respectively). The well-established gender gap persisted in all age groups across time but was considerably smaller in older adults compared to children and young adults. CONCLUSION: Overall, the ADHD case-finding algorithm was found to be a valid tool to assess the epidemiology of ADHD in Canadian primary care practice. The increased prevalence of ADHD between 2008 and 2015 may reflect an improvement in the recognition and treatment of this disorder within primary care.

Quality of Chronic Kidney Disease Management in Canadian Primary Care.

Importance: Although patients with chronic kidney disease (CKD) are routinely managed in primary care settings, no nationally representative study has assessed the quality of care received by these patients in Canada. Objective: To evaluate the current state of CKD management in Canadian primary care practices to identify care gaps to guide development and implementation of national quality improvement initiatives. Design, Setting, and Participants: This cross-sectional study leveraged Canadian Primary Care Sentinel Surveillance Network data from January 1, 2010, to December 31, 2015, to develop a cohort of 46 162 patients with CKD managed in primary care practices. Data analysis was performed from August 8, 2018, to July 31, 2019. Main Outcomes and Measures: The study examined the proportion of patients with CKD who met a set of 12 quality indicators in 6 domains: (1) detection and recognition of CKD, (2) testing and monitoring of kidney function, (3) use of recommended medications, (4) monitoring after initiation of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs), (5) management of blood pressure, and (6) monitoring for glycemic control in those with diabetes and CKD. The study also analyzed associations of divergence from these quality indicators. Results: The cohort comprised 46 162 patients (mean [SD] age, 69.2 [14.0] years; 25 855 [56.0%] female) with stage 3 to 5 CKD. Only 4 of 12 quality indicators were met by 75% or more of the study cohort. These indicators were receipt of an outpatient serum creatinine test within 18 months after confirmation of CKD, receipt of blood pressure measurement at any time during follow-up, achieving a target blood pressure of 140/90 mm Hg or lower, and receiving a hemoglobin A1c test for monitoring diabetes during follow-up. Indicators in the domains of detection and recognition of CKD, testing and monitoring of kidney function (specifically, urine albumin to creatinine ratio testing), use of recommended medications, and appropriate monitoring after initiation of treatment with ACEIs or ARBs were not met. Only 6529 patients (18.4%) with CKD received a urine albumin test within 6 months of CKD diagnosis, and 3954 (39.4%) had a second measurement within 6 months of an abnormal baseline urine albumin level. Older age (≥85 years) and CKD stage 5 were significantly associated with not satisfying the criteria for the quality indicators across all domains. Across age categories, younger patients (aged 18-49 years) and older patients (≥75 years) were less likely to be tested for albuminuria (314 of 1689 patients aged 18-49 years [18.5%], 1983 of 11 919 patients aged 75-84 years [61.6%], and 614 of 5237 patients aged ≥85 years [11.7%] received the urine albumin to creatinine ratio test within 6 months of initial estimated glomerular filtration rate <60 mL/min per 1.73 m2; P < .001). Patients aged 18 to 49 years were less commonly prescribed recommended medications (222 of 2881 [7.7%]), whereas patients aged 75 to 84 years were prescribed ACEIs or ARBs most frequently (2328 of 5262 [44.2%]; P < .001). Conclusions and Relevance: The findings suggest that management of CKD across primary care practices in Canada varies according to quality indicator. This study revealed potential priority areas for quality improvement initiatives in Canadian primary care practices.

Prevalence and Demographics of CKD in Canadian Primary Care Practices: A Cross-sectional Study.

INTRODUCTION: Surveillance systems enable optimal care delivery and appropriate resource allocation, yet Canada lacks a dedicated surveillance system for chronic kidney disease (CKD). Using data from the Canadian Primary Care Sentinel Surveillance Network (CPCSSN), a national chronic disease surveillance system, this study describes the geographic, sociodemographic, and clinical variations in CKD prevalence in the Canadian primary care context. METHODS: This cross-sectional study included 559,745 adults in primary care in 5 provinces across Canada from 2010 through 2015. Data were analyzed by geographic (urban or rural residence), sociodemographic (age, sex, deprivation index), and clinical (medications prescribed, comorbid conditions) factors, using data from CPCSSN and the Canadian Deprivation Index. CKD stage 3 or higher was defined as 2 estimated glomerular filtration rate (eGFR) values of <60 ml/min per 1.73 m2 more than 90 days apart as of January 1, 2015. RESULTS: Prevalence of CKD was 71.9 per 1000 individuals and varied by geography, with the highest prevalence in rural settings compared with urban settings (86.2 vs. 68.4 per 1000). CKD was highly prevalent among individuals with 3 or more other chronic diseases (281.7 per 1000). Period prevalence of CKD indicated a slight decline over the study duration, from 53.4 per 1000 in 2010 to 46.5 per 1000 in 2014. CONCLUSION: This is the first study to estimate the prevalence of CKD in primary care in Canada at a national level. Results may facilitate further research, prioritization of care, and quality improvement activities to identify gaps and improvement in CKD care.

Mucopolysaccharidosis type II detection by Naïve Bayes Classifier: An example of patient classification for a rare disease using electronic medical records from the Canadian Primary Care Sentinel Surveillance Network.

Identifying patients with rare diseases associated with common symptoms is challenging. Hunter syndrome, or Mucopolysaccharidosis type II is a progressive rare disease caused by a deficiency in the activity of the lysosomal enzyme, iduronate 2-sulphatase. It is inherited in an X-linked manner resulting in males being significantly affected. Expression in females varies with the majority being unaffected although symptoms may emerge over time. We developed a Naïve Bayes classification (NBC) algorithm utilizing the clinical diagnosis and symptoms of patients contained within their de-identified and unstructured electronic medical records (EMR) extracted by the Canadian Primary Care Sentinel Surveillance Network (CPCSSN). To do so, we created a training dataset using published results in the scientific literature and from all MPS II symptoms and applied the training dataset and its independent features to compute the conditional posterior probabilities of having MPS II disease as a categorical dependent variable for 506497 male patients. The classifier identified 125 patients with the highest likelihood for having the disease and 18 features were selected to be necessary for forecasting. Next, a Recursive Backward Feature Elimination algorithm was employed, for optimal input features of the NBC model, using a k-fold Cross-Validation with 3 replicates. The accuracy of the final model was estimated by the Validation Set Approach technique and the bootstrap resampling. We also investigated that whether the NBC is as accurate as three other Bayesian networks. The Naïve Bayes Classifier appears to be an efficient algorithm in assisting physicians with the diagnosis of Hunter syndrome allowing optimal patient management.

The Prevalence and Risk for Herpes Zoster Infection in Adult Patients With Diabetes Mellitus in the Canadian Primary Care Sentinel Surveillance Network.

OBJECTIVES: Herpes zoster (HZ) is a common infection in Canada that can result in serious and long-term complications. People with diabetes may be at an increased risk for HZ. The objectives of this study were to develop and validate a case definition of HZ diagnosis based on electronic medical records; determine a prevalence estimate for HZ in adult patients in the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) and assess the association between HZ and diabetes. METHODS: This was a retrospective cross-sectional study. Patients 18 years of age or older who had made at least 1 visit to their primary health-care providers within the past 2 years in the CPCSSN were included. These data came from a 2015 extract of CPCSSN data, and a subsample of 289 patients was used to validate our case definition. Prevalences were estimated for the overall population and for people with diabetes, chronic obstructive pulmonary disease, cancer or HIV. Risk ratios were modelled for these conditions. RESULTS: The sensitivity, specificity, positive predictive value and negative predictive values for HZ were 100%, 73.8%, 83.9% and 100%, respectively. The 1-year prevalence of HZ in the CPCSSN data was 0.32%. The prevalence of HZ was higher in females (0.35%) than in males (0.28%). People with diabetes have an increased risk for HZ infection (RR 2.64, 95% CI 2.34, 2.99). CONCLUSIONS: People with diabetes have an increased risk for the diagnosis of HZ infection in the primary care setting in Canada. Women over the age of 65 years with diabetes and/or other chronic conditions are at greatest risk for developing HZ.

A national surveillance project on chronic kidney disease management in Canadian primary care: a study protocol.

INTRODUCTION: Effective chronic disease care is dependent on well-organised quality improvement (QI) strategies that monitor processes of care and outcomes for optimal care delivery. Although healthcare is provincially/territorially structured in Canada, there are national networks such as the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) as important facilitators for national QI-based studies to improve chronic disease care. The goal of our study is to improve the understanding of how patients with chronic kidney disease (CKD) are managed in primary care and the variation across practices and provinces and territories to drive improvements in care delivery. METHODS AND ANALYSIS: The CPCSSN database contains anonymised health information from the electronic medical records for patients of participating primary care practices (PCPs) across Canada (n=1200). The dataset includes information on patient sociodemographics, medications, laboratory results and comorbidities. Leveraging validated algorithms, case definitions and guidelines will help define CKD and the related processes of care, and these enable us to: (1) determine prevalent CKD burden; (2) ascertain the current practice pattern on risk identification and management of CKD and (3) study variation in care indicators (eg, achievement of blood pressure and proteinuria targets) and referral pattern for specialist kidney care. The process of care outcomes will be stratified across patients' demographics as well as provider and regional (provincial/territorial) characteristics. The prevalence of CKD stages 3-5 will be presented as age-sex standardised prevalence estimates stratified by province and as weighted averages for population rates with 95% CIs using census data. For each PCP, age-sex standardised prevalence will be calculated and compared with expected standardised prevalence estimates. The process-based outcomes will be defined using established methods. ETHICS AND DISSEMINATION: The CPCSSN is committed to high ethical standards when dealing with individual data collected, and this work is reviewed and approved by the Network Scientific Committee. The results will be published in peer-reviewed journals and presented at relevant national and international scientific meetings.

Trends in antidepressant prescribing to children and adolescents in Canadian primary care: A time-series analysis.

PURPOSE: The purpose of this study was to describe the trends and patterns of antidepressant (AD) prescribing to children and adolescents in Canadian primary care before and after the black-box warning in 2004. METHODS: Prescription data from the Canadian Primary Care Sentinel Surveillance Network, a repository of primary care data on over 1 million patients, was used to analyze AD prescribing to children (8-11 y) and adolescents (12-18 y) between 2000 and 2014. Interrupted time series analyses were used to assess the impact of the 2004 black-box warning on the prescribing levels of ADs. RESULTS: The 2004 black-box warning had a significant and immediate effect on the prescribing of AD. However, this drop was not sustained, and 5 years after the advisory AD prescribing rates reversed direction and started to rise. Selective serotonin reuptake inhibitors dominated as the most common AD prescribed throughout the study period, increasing from 66% prior to the black-box warning to 83.12% after 2009. CONCLUSIONS: The black-box warning effectively reduced AD prescribing in primary care for approximately 5 years before a reversal back to a positive rate of prescribing. This rebounding could reflect an emerging consensus about the trade-off in risks and benefits.

Representativeness of patients and providers in the Canadian Primary Care Sentinel Surveillance Network: a cross-sectional study.

BACKGROUND: The Canadian Primary Care Sentinel Surveillance Network (CPCSSN) has established a national repository of primary care patient health data that is used for both surveillance and research. Our main objective was to determine how representative the data for patients and primary care practitioners in the CPCSSN are when compared with the Canadian population. METHODS: In this cross-sectional study, we compared the 2013 CPCSSN patient sample with age and sex information from the 2011 census. The CPCSSN provider sample in 2013 was compared with the 2013 National Physician Survey. Results were stratified by 5 clinically relevant age categories and sex, and male-to-female ratios were calculated. RESULTS: Patients who were 65 years of age and older represented 20.4% of the CPCSSN sample but only represented 14.8% of the Canadian population (2011 census). Among young adults (20-39 yr), 39.3% fewer men than women visited their primary care practitioner within 2 years. CPCSSN sample practitioners were more likely to be under 45 years of age, more likely to be female and more likely to be in an academic practice. INTERPRETATION: It is important to consider adjusting for age and sex when using CPCSSN data. CPCSSN practitioners are likely not representative of family physicians; therefore, CPCSSN needs to recruit more nonacademic practices, community clinics and practices that have a larger proportion of male providers.