Trends in systematic recording errors of blood pressure and association with outcomes in Canadian and UK primary care data: a retrospective observational study

Introduction End digit preference (EDP) or systematic bias in the recording of blood pressure (BP) measurement is prevalent in primary care: up to 60% of BP readings end in zero. High blood pressure (BP) is a leading cause of increased morbidity in adults and errors in measurement may contribute to increased rate of adverse cardiovascular outcomes. Objectives and Approach We studied EDP trends, uptake of Automated Office BP (AOBP) measurement, and cardiovascular outcomes in the UK and Canada.This is a retrospective observational study using routinely collected Electronic Medical Record data for patients age 18 or more. We used bootstrap method to estimate the odds ratios where logistic regression was fitted on one thousand independently sampled replicates of the CPCSSN and RCGP datasets. We implemented the unsupervised algorithm of k-nearest neighbor across all sites to find the optimal decision boundary to classify the sites into the three categories: (1) strong EDP; (2) some EDP; (3) no EDP. Results The mean rate of end digit zero for both systolic and diastolic BP decreased from 26.6% in 2006 to 15.4% in 2015 in Canada and from 24.2% in 2001 to 17.3% in 2015 in the U.K. There was a gradual decline in EDP in the three years following the purchase of an AOBP machine. Sites categorized as having high levels of EDP had lower mean sBP levels than sites with potentially no EDP in both Canada and UK. Patients in sites with high levels of EDP had higher yearly prevalence of stroke (Standardized morbidity ration or SMR 1.11), myocardial infarcts (SMR 1.15), and angina (SMR 1.27) than patients in sites with no EDP. Conclusion/Implications There is systematic recording errors including rounding down of BP readings associated with higher rates of EDP and presumably more use of manual BP measurement. Higher rates of EDP were associated with greater prevalence of adverse cardiovascular outcomes. Consideration should be given to using AOBP machines in primary care

Association between neighbourhood walkability and metabolic risk factors influenced by physical activity: a cross-sectional study of adults in Toronto, Canada.

OBJECTIVE: To determine whether neighbourhood walkability is associated with clinical measures of obesity, hypertension, diabetes and dyslipidaemia in an urban adult population. DESIGN: Observational cross-sectional study. SETTING: Urban primary care patients. PARTICIPANTS: 78 023 Toronto residents, aged 18 years and over, who were formally rostered or had at least 2 visits between 2012 and 2014 with a primary care physician participating in the University of Toronto Practice Based Research Network (UTOPIAN), within the Canadian Primary Care Sentinel Surveillance Network (CPCSSN). MAIN OUTCOME MEASURES: Differences in average body mass index (BMI), systolic and diastolic blood pressure, fasting blood glucose, haemoglobin A1c (HbA1C), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein and triglyceride between residents in the highest versus the lowest quartile of neighbourhood walkability, as estimated using multivariable linear regression models and stratified by age. Outcomes were objectively measured and were retrieved from primary care electronic medical records. Models adjusted for age, sex, smoking, medications, medical comorbidities and indices of neighbourhood safety and marginalisation. RESULTS: Compared with those in the lowest walkability quartile, individuals in the highest quartile had lower mean BMI (-2.64 kg/m2, 95% CI -2.98 to -2.30; p<0.001), systolic blood pressure (-1.35 mm Hg, 95% CI -2.01 to -0.70; p<0.001), diastolic blood pressure (-0.60 mm Hg, 95% CI 1.06 to -0.14; p=0.010) and HbA1c (-0.063%, 95% CI -0.11 to -0.021; p=0.003) and higher mean HDL (0.052 mmol/L, 95% CI 0.029 to 0.075; p<0.001). In age-stratified analyses, differences in the mean BMI were consistently observed for adults aged 18 to under 40 (-4.44 kg/m2, 95% CI -5.09 to -3.79; p<0.001), adults aged 40-65 (-2.74 kg/m2, 95% CI -3.24 to -2.23; p<0.001) and adults aged over 65 (-0.87 kg/m2, 95% CI -1.48 to -0.26; p=0.005). CONCLUSIONS: There was a clinically meaningful association between living in the most walkable neighbourhoods and having lower BMI in adults of all ages

Would you like to add a weight after this blood pressure, doctor? Discovery of potentially actionable associations between the provision of multiple screens in primary care

The CPCSSN was funded through a contribution agreement with the Public Health Agency of Canada.Rationale, aims, and objective:  Guidelines recommend screening for risk factors associated with chronic diseases but current electronic prompts have limited effects. Our objective was to discover and rank associations between the presence of screens to plan more efficient prompts in primary care. Methods:  Risk factors with the greatest impact on chronic diseases are associated with blood pressure, body mass index, waist circumference, glycaemic and lipid levels, smoking, alcohol use, diet, and exercise. We looked for associations between the presence of screens for these in electronic medical records. We used association rule mining to describe relationships among items, factor analysis to find latent categories, and Cronbach α to quantify consistency within latent categories. Results:  Data from 92 140 patients in or around Toronto, Ontario, were included. We found positive correlations (lift >1) between the presence of all screens. The presence of any screen was associated with confidence greater than 80% that other data on items with high prevalence (blood pressure, glycaemic and lipid levels, or smoking) would also be present. A cluster of rules predicting the presence of blood pressure were ranked highest using measures of interestingness such as standardized lift. We found 3 latent categories using factor analysis; these were laboratory tests, vital signs, and lifestyle factors; Cronbach α ranged between .58 for lifestyle factors and .88 for laboratory tests. Conclusions:  Associations between the provision of important screens can be discovered and ranked. Rules with promising combinations of associated screens could be used to implement data driven alerts.Publisher PDFPeer reviewe

Principles and operational model for governing Diabetes Action Canada’s data repository for patient-oriented research

Diabetes Action Canada is developing a data repository andregistry of potential research participants to support research,QI, and service to improve diabetes care. Central to the repositoryare pseudonymised linkable electronic medical records (EMRs) from family practices that are participating in theCanadian Primary Care Sentinel Surveillance Network (CPCSSN).Publisher PD

Data on Patient Record Trajectory for Linkage (DataPRinT Linkage).

The linkage of Electronic Medical Records, Administrative and other data sources is highly valuable for research and health system monitoring. Once linked, combined resources can be analyzed to provide the answers to a variety of health questions that otherwise could not be answered. However, legislative and administrative barriers, including lengthy processes for data sharing agreements, may preclude timely linkage which is a key requirement during pandemics. Objective To develop a method using a patient’s health trajectory to probabilistically link primary care Electronic Medical Record (EMR) data with administrative and other data, without the need to transfer large datasets or identifiable information. To determine the legislative feasibility, accuracy and validity of this linkage process. Study Design Identify data strings that do not directly identify patients and could be used as unique linkage variables. The data strings, which we are calling dataprints, are sufficiently similar over time in different databases. One example in Ontario, Canada, is the pattern of submitted health claims. For every patient seen by a family physician, there exists a unique pattern of dates/billing codes/diagnoses over time. These unique patterns are reasonably similar in EMR and administrative datasets. We will apply an algorithm which turns the string in the selected dataprints to an irreversibly hashed code for each person. The hashed code and no additional information will be provided by both data controllers to a trusted-third party who will determine which records match and send a mapping table to both. This enables analyses to be run in parallel, without divulging any direct person identifiers. Dataset Individuals contained in the University of Toronto Practice Based Research Network (UTOPIAN). Outcome Measures Linkage quality will be assessed by the number of true matches and represented by sensitivity, specificity and positive and negative predictive values. Results The method will be evaluated against a validated, deterministically linked reference standard at North York General Hospital using de-identified EMR and hospital data. Results will inform processes to enable analyses across datasets while adhering to privacy legislation

Participatory governance over research in an academic research network : the case of Diabetes Action Canada

This work was supported by Diabetes Action Canada, which is funded, in part, through a Canadian Institutes of Health Research chronic disease network grant under the Strategy for Patient-Oriented Research (Funding Reference number: SCA 145101).Digital data generated in the course of clinical care are increasingly being leveraged for a wide range of secondary purposes. Researchers need to develop governance policies that can assure the public that their information is being used responsibly. Our aim was to develop a generalisable model for governance of research emanating from health data repositories that will invoke the trust of the patients and the healthcare professionals whose data are being accessed for health research. We developed our governance principles and processes through literature review and iterative consultation with key actors in the research network including: a data governance working group, the lead investigators and patient advisors. We then recruited persons to participate in the governing and advisory bodies. Our governance process is informed by eight principles: (1) transparency; (2) accountability; (3) follow rule of law; (4) integrity; (5) participation and inclusiveness; (6) impartiality and independence; (7) effectiveness, efficiency and responsiveness and (8) reflexivity and continuous quality improvement. We describe the rationale for these principles, as well as their connections to the subsequent policies and procedures we developed. We then describe the function of the Research Governing Committee, the majority of whom are either persons living with diabetes or physicians whose data are being used, and the patient and data provider advisory groups with whom they consult and communicate. In conclusion, we have developed a values-based information governance framework and process for Diabetes Action Canada that adds value over-and-above existing scientific and ethics review processes by adding a strong patient perspective and contextual integrity. This model is adaptable to other secure data repositories.Publisher PDFPeer reviewe

The impact of treatment adherence for patients with diabetes and hypertension on cardiovascular disease risk : a protocol for a retrospective cohort study, 2008-2018

The study received partial in-kind funding from Diabetes Action Canada (503854).Background: Cardiovascular disease (CVD) is the leading cause of death globally and in Canada. Diabetes and hypertension are major risk factors for CVD events. Despite the increasing availability of effective treatments, the majority of diabetic and hypertensive patients do not have adequate blood pressure and glycemic control. One of the major contributors is poor treatment adherence. Objective: This study aims to evaluate the impact of treatment adherence for patients with both diabetes and hypertension on acute severe CVD events and intermediate clinical outcomes in Canadian primary care settings. Methods: We will conduct a population-based retrospective cohort study of patients living with both diabetes and hypertension in Ontario, Canada, between January 1, 2008, and March 31, 2018. The Social Cognitive Theory will be used as a conceptual framework by which to frame the reciprocal relationship between treatment adherence, personal factors, and environmental determinants and how this interplay impacts CVD events and clinical outcomes. Data will be derived from the Diabetes Action Canada National Data Repository. A time-varying Cox proportional hazards model will be used to estimate the impacts of treatment adherence on CVD morbidity and mortality. Multivariable linear regression models and hierarchical regression models will be used to estimate the associations between treatment adherence of different medication categories and intermediate clinical outcomes. Our primary outcome is the association between treatment adherence and the risk of acute severe CVD events, including CVD mortality. The secondary outcome is the association between treatment adherence and intermediate clinical outcomes including diastolic and systolic blood pressures, glycated hemoglobin, low-density lipoprotein cholesterol, and total cholesterol. Owing to data limitation, we use medication prescriptions as a proxy to estimate treatment adherence. We assume that a patient adhered to medications if she or he had any prescription record in the 4 preceding quarters and 1 quarter after each quarter of interest. Acute severe CVD events are defined based on the World Health Organization’s Monitoring Trends and Determinants in Cardiovascular Disease Project, including acute coronary heart disease, stroke, and heart failure. As causes of death are not available, the number of CVD deaths will be computed using the most recent systolic blood pressure distributions and the population attributable risks related to systolic blood pressure level. Results: The project was funded by Diabetes Action Canada (reference number: 503854) and approved by the University of Toronto Research Ethics Board (reference number: 36065). The project started in June 2018 and is expected to be finished by September 2019. Conclusions: The findings will be helpful in identifying the challenges of treatment adherence for diabetic and hypertensive patients in primary care settings. This will also help to develop intervention strategies to promote treatment adherence for patients with multi-morbidities.Publisher PDFPeer reviewe

Impact of the Diabetes Canada Guideline Dissemination Strategy on the prescription of vascular protective medications : a retrospective cohort study, 2010-2015

Funding: Diabetes CanadaOBJECTIVE: The 2013 Diabetes Canada guidelines launched targeted dissemination tools and a simple assessment for vascular protection. We aimed to 1) examine changes associated with the launch of the 2013 guidelines and additional dissemination efforts in the rates of vascular protective medications prescribed in primary care for older patients with diabetes and 2) examine differences in the rates of prescriptions of vascular protective medications by patient and provider characteristics. RESEARCH DESIGN AND METHODS: The study population included patients (≥40 years of age) from the Canadian Primary Care Sentinel Surveillance Network with type 2 diabetes and at least one clinic visit from April 2010 to December 2015. An interrupted time series analysis was used to assess the proportion of eligible patients prescribed a statin, ACE inhibitor (ACEI)/angiotensin receptor blocker (ARB), or antiplatelet prescription in each quarter. Proton pump inhibitor (PPI) prescriptions were the reference control. RESULTS: A dynamic cohort was used where participants were enrolled each quarter using a prespecified set of conditions (range 25,985-70,693 per quarter). There were no significant changes in statin (P = 0.43), ACEI/ARB (P = 0.42), antiplatelet (P = 0.39), or PPI (P = 0.16) prescriptions at baseline (guideline intervention). After guideline publication, there was a significant change in slope for statin (-0.52% per quarter, SE 0.15, P < 0.05), ACEI/ARB (-0.38% per quarter, SE 0.13, P < 0.05) and reference PPI (-0.18% per quarter, SE 0.05, P < 0.05) prescriptions. CONCLUSIONS: There was a decrease in prescribing trends over time that was not specific to vascular protective medications. More effective knowledge translation strategies are needed to improve vascular protection in diabetes in order for patients to receive the most effective interventions.PostprintPeer reviewe

Over-use of thyroid testing in Canadian and UK primary care in frequent attenders : a cross-sectional study

Dr Greiver is supported through the Gordon F. Cheesbrough Research Chair in Family and Community Medicine from North York General Hospital.Background Thyroid stimulating hormone (TSH) is a common test used to detect and monitor clinically significant hypo- and hyperthyroidism. Population based screening of asymptomatic adults for thyroid disorders is not recommended. Objective The research objectives were to determine patterns of TSH testing in Canadian and English primary care practices, as well as patient and physician practice characteristics associated with testing TSH for primary care patients with no identifiable indication. Methods In this two-year cross-sectional observational study, Canadian and English electronic medical record databases were used to identify patients and physician practices. Cohorts of patients aged 18 years or older, without identifiable indications for TSH testing, were generated from these databases. Analyses were performed using a random-effects logistic regression to determine patient and physician practice characteristics associated with increased testing. We determined the proportion of TSH tests done concurrently with at least one common screening blood test (lipid profile or hemoglobin A1c). Standardized proportions of TSH test per family practice were used to examine the heterogeneity in the populations. Results At least one TSH test was done in 35.97 % (N=489,663) of Canadian patients and 29.36% (N=1,030,489) of English patients. Almost all TSH tests in Canada and England (95.69% and 99.23% respectively) were within the normal range (0.40-5.00 mU/L). A greater number of patient-physician encounters was the strongest predictor of TSH testing. 51.40% of TSH tests in Canada and 76.55% in England were done on the same day as at least one other screening blood test. There was no association between practice size and proportion of asymptomatic patients tested. Conclusions This comparative binational study found TSH patterns suggestive of over-testing and potentially thyroid disorder screening in both countries. There may be significant opportunities to improve appropriateness of TSH ordering in Canada and England and therefore improve allocation of limited system resources.PostprintPeer reviewe