Ethnic differences in acute heart failure outcomes in Ontario

Abstract

Background: Previous studies have identified ethnic differences in outcomes after episodes of acute heart failure in natives of Asia as compared to those of Europe. Whether these ethnic differences in outcomes would still exist, years after migration to a different geographical and cultural setting remain unclear. We investigated the one-year mortality after an episode of acute heart failure admission in Ontario residents of South Asian and Chinese descent as compared to the General Population.

Methods: We conducted a population-based, retrospective cohort study of adult Ontarions who were hospitalized for AHF between April 1, 2010 and March 31, 2016. Ethnicity was categorized using validated surname-based algorithms. The primary outcome was all-cause one-year mortality. Mortality rates were calculated using the Kaplan-Meier method. The relative hazard of death was assessed using a multivariable Cox proportional hazard model.

Results: Of 82,125 patients, 1287 (1.6%) were Chinese, 1662 (2.0%) were South Asians, and the remaining 79,176 (96.4%) were of the General Population. The risk of mortality was markedly lower amongst South Asians (adjusted HR 0.81, 95% CI [0.73-0.89]) relative to the General Population. There was no statistically significant difference in the risk of mortality between Chinese and the General Population (adjusted HR 1.00 [0.91-1.10]). In addition, guideline-directed medical therapies were associated with similar survival benefit in patients of all three ethnic origins.

Conclusions: We found a lower risk of one-year mortality after acute heart failure hospitalization amongst South Asians compared to Chinese and the General Population, and similar benefit of medical therapy in all three groups. Further studies are needed to explore the etiologies of these ethnic disparities to truly improve outcomes at the population level.

Keywords: Acute heart failure; Ethnicity; Medical therapy; Survival.