Differences in coronary artery disease complexity and associations with mortality and hospital admissions among First Nations and non-First Nations patients undergoing angiography: a comparative retrospective matched cohort study.

BACKGROUND: First Nations people are more likely than the general population to experience long-term adverse health outcomes after coronary angiography. Our aim was to quantify the extent of coronary artery disease among First Nations and non-First Nations patients undergoing angiography to investigate differences in coronary artery disease and related health disparities. METHODS: We conducted a retrospective matched cohort study to compare health outcomes of First Nations and non-First Nations adult patients (> 18 yr) who underwent index angiography between Apr. 1, 2008, and Mar. 31, 2012, in Manitoba, Canada. The SYNTAX Score was used to measure and compare severity of coronary artery disease between groups. Primary outcomes of all-cause and cardiovascular mortality were compared between groups using Cox proportional hazard models adjusted by SYNTAX Score results and weighted by the inverse probability of being First Nations. Secondary outcomes included all-cause and cardiovascular-related hospital admissions. RESULTS: The cohort consisted of 277 matched pairs of First Nations and non-First Nations patients undergoing angiography; the average age of patients was 56.0 (standard deviation 11.7) years. The median SYNTAX Score results and patient distributions across categories in the matched paired cohort groups were not significantly different. Although proportionally First Nations patients showed worse health outcomes, mortality risks were similar in the weighted sample, even after controlling for revascularization and SYNTAX Score results. Secondary outcomes showed that adjusted risks for hospital admission for acute myocardial infarction (adjusted hazard ratio [HR] 3.03, 95% confidence interval [CI] 1.40-6.55) and for congestive heart failure (adjusted HR 3.84, 95% CI 1.37-10.78) were significantly higher among First Nations patients in the weighted sample. INTERPRETATION: The extent of coronary artery disease among matched cohort groups of First Nations and non-First Nations patients appears similar, and controlling for baseline sociodemographic characteristics, coronary artery disease risk factors and SYNTAX Score results explained higher mortality risk and most hospital admissions among First Nations patients. Although there is a need to decrease risk factors for coronary artery disease among First Nations populations, addressing individuals' behaviour without considering root causes underlying risk factors for coronary artery disease will fail to decrease health outcome disparities among First Nations patients undergoing angiography.

Cardiovascular Medication Use and Long-Term Outcomes of First Nations and Non-First Nations Patients Following Diagnostic Angiography: A Retrospective Cohort Study.

Background In Canada, First Nations (FN) people are at greater risk of mortality than the general population following index angiography. This disparity has not been investigated while considering guideline-recommended cardiovascular medication use. Methods and Results Retrospective analysis of administrative health data investigated patterns of medication dispensation during the first year after index angiography among patients in Manitoba, Canada. Medication possession ratios (MPRs) reflecting the percentage of days in which medications were supplied were calculated separately for ß-blockers, angiotensin-converting enzyme inhibitors, statins, and antiplatelets (clopidogrel). Patients were assigned to 1 of 4 categories: (1) not dispensed (0% MPR), (2) low (1-39% MPR), (3) intermediate (40-79% MPR), (4) high (≥80% MPR). Cox regression models that adjusted for MPR categories were used to explore the association between FN patients and both 5-year all-cause mortality and cardiovascular mortality. FN patients were less likely to have an intermediate MPR (odds ratio: 0.75; 95% CI, 0.57-0.99) or a high MPR (odds ratio: 0.64; 95% CI, 0.50-0.81) for statin medications than non-FN patients. FN patients also had higher adjusted risks of all-cause and cardiovascular mortality than non-FN patients (hazard ratio, all-cause: 1.54 [95% CI, 1.25-1.89]; cardiovascular: 1.62 [95% CI, 1.16-2.25]). Conclusions FN status was independently associated with intermediate and high MPRs for statins during the first year following index angiography among patients with known ischemic heart disease. Differences in MPR categories did not explain the disparity in all-cause and cardiovascular mortality between the 2 populations. Reduction of cardiovascular disparities may be best addressed using primary prevention strategies that include decolonizing policies and practices.

Health Outcome and Follow-up Care Differences Between First Nation and Non-First Nation Coronary Angiogram Patients: A Retrospective Cohort Study.

BACKGROUND: First Nations (FN) people experience high rates of ischemic heart disease (IHD) morbidity and mortality. Increasing access to angiography may lead to improved outcomes. We compared various outcomes and follow-up care post-index angiography between FN and non-FN patients. METHODS: All index angiography patients in Manitoba were identified between April 1, 2000 and March 31, 2009 and categorized into acute myocardial infarction (AMI) or non-AMI groups based on whether their angiogram occurred within 7 days of an AMI. Cox proportional hazard models estimated associations between FN status and outcomes related to mortality, subsequent hospitalizations, revascularizations, and physician visits. RESULTS: Cardiovascular mortality was higher among FN patients in the non-AMI group (hazard ratio [HR] = 1.50, 95% confidence interval [CI], 1.17-1.94) and in the AMI group (HR = 1.57, 95% CI, 1.05-2.35). FN patients were also more likely to have a subsequent hospitalization for AMI (HR = 2.26, 95% CI, 1.79-2.85) in the non-AMI group. FN patients in the non-AMI group were less likely to receive percutaneous coronary intervention (HR = 0.85, 95% CI, 0.73-0.99) and more likely to undergo coronary artery bypass graft (HR = 1.26, 95% CI, 1.10-1.45). FN patients in both groups were less likely to visit a cardiologist/cardiac surgeon, internal medicine specialist, or family physician within 3 months and 1 year of angiography. CONCLUSIONS: Cardiovascular health and follow-up care outcomes of FN and non-FN patients who undergo angiography are not the same. Addressing Indigenous determinants of health are necessary to improve cardiovascular outcomes.