Contemporary Outcomes of Acute Coronary Syndromes in Indigenous Compared With Non-Indigenous Patients: A Northern Saskatchewan Perspective

Background: In patients presenting with an acute coronary syndrome (ACS), the impact of efforts to bridge historical care gaps between Indigenous and non-Indigenous patients remains limited. Methods: For consecutive ACS presentations (ST-segment elevation myocardial infarction [STEMI] and non- ST-segment elevation myocardial infarction [NSTEMI]/unstable angina [UA], respectively) at the Royal University Hospital, Saskatoon, we compared self-identified Indigenous and non-Indigenous patients' demographics, treatments, and all-cause mortality (in-hospital and within 3 years). We used propensity score inverse probability weighting to mitigate confounding and Cox regression models to estimate the adjusted hazard ratio (aHR) for all-cause mortality. Results: Of 3946 ACS patients, 37.2% (n = 1468) were STEMI, of whom 11.3% (n = 166) were Indigenous. Of the NSTEMI/UA (n = 2478), 12.6% (n = 311), were Indigenous. Overall, Indigenous compared with non-Indigenous patients were likely to be younger, female, have higher risk burden, and live more remotely; Indigenous STEMI patients triaged to primary percutaneous coronary intervention had longer times from fi rst medical contact to device, and Indigenous NSTEMI/UA patients more likely to present with heart failure, cardiac arrest, and cardiogenic shock. No significant differences were noted for in-hospital mortality (STEMI 8.4% vs 5.7% [P = 0.16], NSTEMI/UA 1.9% vs 1.6% [P = 0.68]), although in follow-up, Indigenous STEMI patients were associated with a higher all-cause mortality risk (aHR 1.98, 95% CI 1.19-3.31; P = 0.009) with no between-group differences evident for NSTEMI/UA (aHR 1.03, 95% CI 0.63 1.69; P = 0.91). Conclusions: Indigenous compared with non-Indigenous patients presenting with an ACS had higher cardiovascular risk profiles and consequent residual mortality risk. Improving primary care and intensifying secondary risk reduction, particularly for Indigenous patients, will substantially modify ACS outcomes in Saskatchewan.