Anna Chu

The Cardiovascular Health in Ambulatory Care Research Team (CANHEART) Using Big Data to Measure and Improve Cardiovascular Health and Healthcare Services

Background—The CArdiovascular HEalth in Ambulatory care Research Team (CANHEART) is conducting a unique, population-based observational research initiative aimed at measuring and improving cardiovascular health and the quality of ambulatory cardiovascular care provided in Ontario, Canada. A particular focus will be on identifying opportunities to improve the primary and secondary prevention of cardiovascular events in Ontario’s diverse multiethnic population. Methods and Results—A population-based cohort comprising 9.8 million Ontario adults ≥20 years in 2008 was assembled by linking multiple electronic survey, health administrative, clinical, laboratory, drug, and electronic medical record databases using encoded personal identifiers. The cohort includes ≈9.4 million primary prevention patients and ≈400 000 secondary prevention patients. Follow-up on clinical events is achieved through record linkage to comprehensive hospitalization, emergency department, and vital statistics administrative databases. Profiles of cardiovascular health and preventive care will be developed at the health region level, and the cohort will be used to study the causes of regional variation in the incidence of major cardiovascular events and other important research questions. Conclusions—Linkage of multiple databases will enable the CANHEART study cohort to serve as a powerful big data resource for scientific research aimed at improving cardiovascular health and health services delivery. Study findings will be shared with clinicians, policy makers, and the public to facilitate population health interventions and quality improvement initiatives.

The Incidence of Major Cardiovascular Events in Immigrants to Ontario, Canada: The CANHEART Immigrant Study.

Background —Immigrants from ethnic minority groups represent an increasing proportion of the population in many high-income countries but little is known about the causes and amount of variation between various immigrant groups in the incidence of major cardiovascular events. Methods and Results —We conducted the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) Immigrant study, a big data initiative, linking information from Citizenship and Immigration Canadas Permanent Resident database to nine population-based health databases. A cohort of 824 662 first-generation immigrants aged 30 to 74 as of January 2002 from eight major ethnic groups and 201 countries of birth who immigrated to Ontario, Canada between 1985 and 2000 were compared to a reference group of 5.2 million long-term residents. The overall 10-year age-standardized incidence of major cardiovascular events was 30% lower among immigrants compared with long-term residents. East Asian immigrants (predominantly ethnic Chinese) had the lowest incidence overall (2.4 in males, 1.1 in females per 1000 person-years) but this increased with greater duration of stay in Canada. South Asian immigrants, including those born in Guyana had the highest event rates (8.9 in males, 3.6 in females per 1000 person-years), along with immigrants born in Iraq and Afghanistan. Adjustment for traditional risk factors reduced but did not eliminate differences in cardiovascular risk between various ethnic groups and long-term residents. Conclusions —Striking differences in the incidence of cardiovascular events exist among immigrants to Canada from different ethnic backgrounds. Traditional risk factors explain part but not all of these differences.Background— Immigrants from ethnic minority groups represent an increasing proportion of the population in many high-income countries, but little is known about the causes and amount of variation between various immigrant groups in the incidence of major cardiovascular events. Methods and Results— We conducted the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) Immigrant Study, a big data initiative, linking information from Citizenship and Immigration Canada’s Permanent Resident database to 9 population-based health databases. A cohort of 824 662 first-generation immigrants aged 30 to 74 as of January 2002 from 8 major ethnic groups and 201 countries of birth who immigrated to Ontario, Canada between 1985 and 2000 were compared with a reference group of 5.2 million long-term residents. The overall 10-year age-standardized incidence of major cardiovascular events was 30% lower among immigrants than among long-term residents. East Asian immigrants (predominantly ethnic Chinese) had the lowest incidence overall (2.4 in males, 1.1 in females per 1000 person-years), but this increased with greater duration of stay in Canada. South Asian immigrants, including those born in Guyana, had the highest event rates (8.9 in males, 3.6 in females per 1000 person-years), along with immigrants born in Iraq and Afghanistan. Adjustment for traditional risk factors reduced but did not eliminate the differences in cardiovascular risk between various ethnic groups and long-term residents. Conclusions— Striking differences in the incidence of cardiovascular events exist among immigrants to Canada from different ethnic backgrounds. Traditional risk factors explain a part but not all of these differences.

Estimating the prevalence of heterozygous familial hypercholesterolaemia: a systematic review and meta-analysis

Objectives Heterozygous familial hypercholesterolaemia (FH) confers a significant risk for premature cardiovascular disease (CVD). However, the estimated prevalence of FH varies substantially among studies. We aimed to provide a summary estimate of FH prevalence in the general population and assess variations in frequency across different sociodemographic characteristics. Setting, participants and outcome measures We searched MEDLINE, EMBASE, Global Health, the Cochrane Library, PsycINFO and PubMed for peer-reviewed literature using validated strategies. Results were limited to studies published in English between January 1990 and January 2017. Studies were eligible if they determined FH prevalence using clinical criteria or DNA-based analyses. We determined a pooled point prevalence of FH in adults and children and assessed the variation of the pooled frequency by age, sex, geographical location, diagnostic method, study quality and year of publication. Estimates were pooled using random-effects meta-analysis. Differences by study-level characteristics were investigated through subgroups, meta-regression and sensitivity analyses. Results The pooled prevalence of FH from 19 studies including 2 458 456 unique individuals was 0.40% (95% CI 0.29% to 0.52%) which corresponds to a frequency of 1 in 250 individuals. FH prevalence was found to vary by age and geographical location but not by any other covariates. Results were consistent in sensitivity analyses. Conclusions Our systematic review suggests that FH is a common disorder, affecting 1 in 250 individuals. These findings underscore the need for early detection and management to decrease CVD risk.

Quality Indicators of End-of-Life Care in Patients With Cancer: What Rate Is Right?

PURPOSE To develop data-driven and achievable benchmark rates for end-of-life quality indicators using administrative data from four provinces in Canada. METHODS Indicators of end-of-life care were defined and measured using linked administrative data for 33 health regions across British Columbia, Alberta, Ontario, and Nova Scotia. These were emergency department use, intensive care unit admission, physician house calls and home care visits before death, and death in hospital. An empiric benchmark was defined using indicator rates from the top-ranked regions to include the top decile of patients overall. Funnel plots were used to graph each regions age- and sex-adjusted indicator rates along with the overall rate and 95% confidence limits. RESULTS Rates varied approximately two- to four-fold across the regions, with physician house calls showing the greatest variation. Benchmark rates based on the top decile performers were emergency department use, 34%; intensive care unit admission, 2%; physician house calls, 34%; home care visits, 63%; and death in hospital, 38%. With the exception of intensive care unit admission, funnel plots demonstrated that overall indicator rates and their confidence limits were uniformly worse than benchmarks even after adjusting for age and sex. Few regions met the benchmark rates. CONCLUSION There is significant variation in end-of-life quality indicators across regions in four provinces in Canada. Using this studys methods-deriving empiric benchmarks and funnel plots-regions can determine their relative performance with greater context that facilitates priority setting and resource deployment. Applying this studys methods can support quality improvement by decreasing variation and striving for a target.

The Risk of Ischemic Heart Disease and Stroke Among Immigrant Populations: A Systematic Review

BACKGROUND The increasing frequency of global migration to Canada and other high-income countries has highlighted the need for information on the risk of ischemic heart disease (IHD) and stroke among migrant populations. METHODS Using the MEDLINE and EMBASE databases, we conducted an English-language literature review of articles published from 2000 to 2014 to study patterns in the incidence of IHD or stroke in migrant populations to high-income countries. Our search revealed 17 articles of interest. All studies stratified immigrants according to country or region of birth, except 2 from Canada and 1 from Denmark, in which all immigrant groups were analyzed together. RESULTS The risk of IHD or stroke varied by country of origin, country of destination, and duration of residence. In our review we found that most migrant groups to Western Europe were at a similar or higher risk of IHD and stroke compared with the host population. Those at a higher risk included many Eastern European, Middle-Eastern, and South Asian immigrants. When duration of residence was considered, it appeared that in most migrants the risk of IHD worsened over time. In contrast, immigrants overall were at lower risk of myocardial infarction and stroke in Ontario compared with long-term residents of Canada. CONCLUSIONS The risks of IHD and stroke vary widely in immigrant populations in Western Europe. Detailed studies of immigrants to Canada according to country of birth and duration of residence should be undertaken to guide future cardiovascular health promotion initiatives.

Regional variations in ambulatory care and incidence of cardiovascular events

BACKGROUND: Variations in the prevalence of traditional cardiac risk factors only partially account for geographic variations in the incidence of cardiovascular disease. We examined the extent to which preventive ambulatory health care services contribute to geographic variations in cardiovascular event rates. METHODS: We conducted a cohort study involving 5.5 million patients aged 40 to 79 years in Ontario, Canada, with no hospital stays for cardiovascular disease as of January 2008, through linkage of multiple population-based health databases. The primary outcome was the occurrence of a major cardiovascular event (myocardial infarction, stroke or cardiovascular-related death) over the following 5 years. We compared patient demographics, cardiac risk factors and ambulatory health care services across the province’s 14 health service regions, known as Local Health Integration Networks (LHINs), and evaluated the contribution of these variables to regional variations in cardiovascular event rates. RESULTS: Cardiovascular event rates across LHINs varied from 3.2 to 5.7 events per 1000 person-years. Compared with residents of high-rate LHINs, those of low-rate health regions received physician services more often (e.g., 4.2 v. 3.5 mean annual family physician visits, p value for LHIN-level trend = 0.01) and were screened for risk factors more often. Low-rate LHINs were also more likely to achieve treatment targets for hypercholes-terolemia (51.8% v. 49.6% of patients, p = 0.03) and controlled hypertension (67.4% v. 53.3%, p = 0.04). Differences in patient and health system factors accounted for 74.5% of the variation in events between LHINs, of which 15.5% was attributable to health system factors alone. INTERPRETATION: Preventive ambulatory health care services were provided more frequently in health regions with lower cardiovascular event rates. Health system interventions to improve equitable access to preventive care might improve cardiovascular outcomes.

Association of a Blood Glucose Test Strip Quantity-Limit Policy With Patient Outcomes: A Population-Based Study

Importance Given their high costs, payers have considered implementing quantity limits for reimbursement of blood glucose test strips. The effect of these limits on patient outcomes is unknown. Objective To determine whether the introduction of quantity limits for blood glucose test strips in August 2013 was associated with changes in clinical outcomes. Design, Setting, and Participants Cross-sectional time series analysis from April 2008 to March 2015 of residents of Ontario, Canada, aged 19 years and older with diabetes who were eligible for public drug coverage. In a sensitivity analysis, we studied high-volume users of test strips, who were most likely to be affected by the quantity limits. Exposures Eligible patients were stratified into 4 mutually exclusive groups based on diabetes therapy: insulin, hypoglycemia-inducing oral diabetes agents, nonhypoglycemia-inducing oral diabetes agents, and no drug therapy. Main Outcomes and Measures The primary outcome was emergency department visits for hypoglycemia or hyperglycemia, and the secondary outcome was mean hemoglobin A1c (HbA1c) levels. Outcomes were measured for all patients in each quarter, stratified by age group (<65 vs ≥65 years) and diabetes therapy. Results By the end of the study period, 834 309 people met inclusion criteria. Among those younger than 65 years, the rate of hypoglycemia and hyperglycemia declined over the study period (from 4.9 to 3.0 visits per 1000 Ontario drug benefit [ODB]-eligible patients and from 4.2 to 3.6 visits per 1000 ODB-eligible patients, respectively) and was not significantly associated with the introduction of quantity limits (P = .67 and P  = .37, respectively). Similarly, among those aged 65 years and older, rates of hypoglycemia and hyperglycemia declined over the study period (from 2.9 to 1.3 visits per 1000 eligible patients and from 0.8 to 0.5 visits per 1000 eligible patients, respectively) and was not significantly associated with the introduction of quantity limits (P = .12 and P = .24, respectively). Results were consistent for the secondary outcome of mean HbA1c levels and in the sensitivity analysis of high-volume test strip users. Conclusions and Relevance The imposition of quantity limits for blood glucose test strips was not associated with worsening short-term outcomes, suggesting that these policies can reduce costs associated with test strips without causing patient harm.

Quality of end-of-life cancer care in Canada: a retrospective four-province study using administrative health care data

BACKGROUND The quality of data comparing care at the end of life (eol) in cancer patients across Canada is poor. This project used identical cohorts and definitions to evaluate quality indicators for eol care in British Columbia, Alberta, Ontario, and Nova Scotia. METHODS This retrospective cohort study of cancer decedents during fiscal years 2004-2009 used administrative health care data to examine health service quality indicators commonly used and previously identified as important to quality eol care: emergency department use, hospitalizations, intensive care unit admissions, chemotherapy, physician house calls, and home care visits near the eol, as well as death in hospital. Crude and standardized rates were calculated. In each province, two separate multivariable logistic regression models examined factors associated with receiving aggressive or supportive care. RESULTS Overall, among the identified 200,285 cancer patients who died of their disease, 54% died in a hospital, with British Columbia having the lowest standardized rate of such deaths (50.2%). Emergency department use at eol ranged from 30.7% in Nova Scotia to 47.9% in Ontario. Of all patients, 8.7% received aggressive care (similar across all provinces), and 46.3% received supportive care (range: 41.2% in Nova Scotia to 61.8% in British Columbia). Lower neighbourhood income was consistently associated with a decreased likelihood of supportive care receipt. INTERPRETATION We successfully used administrative health care data from four Canadian provinces to create identical cohorts with commonly defined indicators. This work is an important step toward maturing the field of eol care in Canada. Future work in this arena would be facilitated by national-level data-sharing arrangements.

The Cardiovascular Health in Ambulatory Care Research Team performance indicators for the primary prevention of cardiovascular disease: a modified Delphi panel study

BACKGROUND High-quality ambulatory care can reduce cardiovascular disease risk, but important gaps exist in the provision of cardiovascular preventive care. We sought to develop a set of key performance indicators that can be used to measure and improve cardiovascular care in the primary care setting. METHODS As part of the Cardiovascular Health in Ambulatory Care Research Team initiative, we established a 14-member multidisciplinary expert panel to develop a set of indicators for measuring primary prevention performance in ambulatory cardiovascular care. We used a 2-stage modified Delphi panel process to rate potential indicators, which were identified from the literature and national cardiovascular organizations. The top-rated indicators were pilot tested to determine their measurement feasibility with the use of data routinely collected in the Canadian health care system. RESULTS A set of 28 indicators of primary prevention performance were identified, which were grouped into 5 domains: risk factor prevalence, screening, management, intermediate outcomes and long-term outcomes. The indicators reflect the major cardiovascular risk factors including smoking, obesity, hypertension, diabetes, dyslipidemia and atrial fibrillation. All indicators were determined to be amenable to measurement with the use of population-based administrative (physician claims, hospital admission, laboratory, medication), survey or electronic medical record databases. INTERPRETATION The Cardiovascular Health in Ambulatory Care Research Team indicators of primary prevention performance provide a framework for the measurement of cardiovascular primary prevention efforts in Canada. The indicators may be used by clinicians, researchers and policy-makers interested in measuring and improving the prevention of cardiovascular disease in ambulatory care settings.

Anxiety, depression, and health-related quality of life in heterozygous familial hypercholesterolemia: A systematic review and meta-analysis

BACKGROUND Heterozygous familial hypercholesterolemia (FH) is a common genetic disease predisposing affected individuals to a high risk of cardiovascular disease. Yet, considerable uncertainty exists regarding its impact on psychosocial wellbeing. OBJECTIVES We performed a systematic review and meta-analysis of the association between FH and symptoms of anxiety and depression, and health-related quality of life (HRQL). METHODS We searched MEDLINE, EMBASE, Global Health, the Cochrane Library, PsycINFO, and PubMed for peer-reviewed literature published in English between January 1, 1990 and January 1, 2018. Quantitative and qualitative studies were eligible if they included patients with confirmed FH and evaluated its association with symptoms of anxiety or depression, or HRQL. We performed a narrative synthesis of studies, including thematic analysis of qualitative studies, and where data permitted, random-effects meta-analysis reporting standardized mean differences (SMD) and 95% confidence intervals. RESULTS We found 10 eligible studies measuring HRQL, depression and anxiety. Random-effects meta-analysis of 4 (n = 4293) and 5 studies (n = 5098), respectively, showed that patients with FH had slightly lower symptoms of anxiety (SMD: -0.29 [95% CI: -0.53, -0.04]) and mental HRQL (SMD: -0.10 [95% -0.20, -0.00]) relative to general population controls. No significant differences existed in depressive symptoms (SMD: 0.04 [95% CI: -0.12, 0.19]) or physical HRQL scores (SMD: 0.02 [95% CI: -0.09, 0.12]). CONCLUSIONS Our systematic review suggests that patients with FH may report small but measurable differences in anxiety symptoms and mental HRQL.