The long-term mortality of an Aboriginal and Torres Strait Islander Australian population after isolated coronary artery bypass graft surgery.

Abstract

Aboriginal and Torres Strait Islander (Indigenous) Australians have an increased prevalence of coronary artery disease and present at a younger age for coronary artery bypass graft surgery (CABG) when compared to non-Indigenous Australians. Studies have reported postoperative outcomes in Indigenous people to be less favourable. Therefore, the aim of this study is to evaluate long term mortality between Indigenous and non-Indigenous people post-CABG. We analysed data on all patients who underwent isolated CABG, with and without cardiopulmonary bypass, at our institution between January 1998 to September 2008. There were 33 395 person-years of survival for analysis with a median follow-up of 13 years (Interquartile range (IQR): 8-16 years). We analysed all-cause mortality with the Kaplan-Meier graph and log-rank test. Univariate and multivariate analysis was performed using a Cox proportional hazards model. The mean age at presentation for Indigenous people was 52 years compared to 65 yr for non-indigenous people. There were 1431 (52.1%) deaths by the study census date, with the overall mortality for Indigenous patients at 49.8% (n= 147) and 52.4% for non-Aboriginal patients (n= 1284). The age and comorbidities adjusted hazard ratio (HR) for all-cause late mortality (median years) was HR=1.712 (95% CI: 1.288-2.277, p< 0.001). Indigenous patients present for CABG at a younger age and have a higher prevalence of comorbidities. Our study demonstrates they have a higher risk of propensity adjusted all-cause long term mortality. Primary and secondary prevention strategies, tailored to Indigenous people, may improve health outcomes in the long-term post-CABG.