Socioeconomic status, access to invasive coronary angiography, and mortality of acute myocardial infarction patients

Abstract

This paper examines the role of socioeconomic status (SES) and access to care in affecting the survival of acute myocardial infarction (AMI) patients. The question is asked in the context of Australia's universal health care system where equity of access is a stated policy objective. We jointly model the probability of patients being admitted to a catheterisation-capable hospital, receiving invasive coronary angiography (ICA), and surviving 30 days post discharge as a recursive system of probit equations. From the recursive system, we are able to disentangle the direct effects of SES on survival from the indirect effects of SES on access. We further interact SES with the short-term catheterisation capacity of admitting hospitals to investigate whether the access gap between SES groups widens when capacity was limited. We make use of hospital administrative data from the state of Victoria to construct a sample of all admissions of AMI episodes in a seven-year period (2004/05-–2011/12). We find that the likelihood of access is significantly lower for socioeconomically disadvantaged patients. However, while access affects the survival probability, these effects are small compared to the direct effects of SES on survival probabilities. We further find that capacity has no effects on access, on average, across all patients, but when interacting with SES, access by disadvantaged patients appears to be impacted more in situations of limited capacity compared to less disadvantaged groups. We show that even in Australia, with its universal health system, SES plays a significant role in affecting the access to care and subsequent survival. The findings suggest that public health strategies to reduce inequality in health should attempt not only to improve access but also address the direct effects of SES.