Investigating the extent and explanations of in-hospital disparities experienced by Aboriginal and Torres Strait Islander people admitted for Acute Coronary Syndrome in South Australia

Introduction: The unacceptable disparity between Aboriginal and non-Aboriginal Australians in cardiovascular outcomes is well recognised. Acute coronary syndrome (ACS) burden is improved with diagnostic coronary angiography and revascularisation during acute admission. Differences in utilisation of these procedures may contribute to poorer outcomes amongst Aboriginal Australians. Objectives: To identify if there was a difference in angiography receipt and subsequent revascularisation between Aboriginal and non-Aboriginal South Australians presenting to major metropolitan public hospitals with ACS. Methods: Admissions to the four major South Australian (SA) public hospitals between 2007-2012 with a principal diagnosis of ACS were sourced from an administrative dataset. Aboriginal and Torres Strait Islander status, demographics and cardiac procedures were determined. Logistic regression modelling identified predictors of: coronary angiography; and, revascularisation in those who receive angiography. Results: Of the 13,701 admissions identified, 274 (2%) were Aboriginal and Torres Strait Islander people, who were younger (5311 vs 7014, p<0.001) and more often female compared to non-Aboriginal people (43% vs 35%, p¼0.009). Unadjusted data showed angiography was performed in 49% of Aboriginal and Torres Strait Islander patients and 46% of non-Aboriginal patients. In multi-variable logistic regression, Aboriginal and Torres Strait Islander status was a significant independent predictor of angiography: 40% less likely to receive angiography compared to non-Aboriginal people (OR 0.61, (0.46-0.81), p¼0.001), following adjustment for age, past history of coronary heart disease (CHD), renal failure, heart failure, airways disease, and interaction effects of age and CHD. This disparity was similar when admissions were analysed in consecutive two-yearly blocks. In angiography patients, 63% of non-Aboriginal patients proceeded to revascularisation compared to 66% of Aboriginal and Torres Strait Islander patients. Regression modelling did not reveal ethnicity as a predictor of revascularisation. Conclusion: Aboriginal patients admitted to SA public hospitals with an ACS are 40% less likely to undergo coronary angiography then their non-Aboriginal counterparts when age and other clinical factors are considered. The reasons for this disparity need to be examined and mechanisms to ameliorate this difference addressed, as this would improve cardiovascular outcomes in these patients.