Low Socioeconomic Status Increases Short-term Mortality of Acute Myocardial Infarction Despite Universal Health Coverage

Background: This nationwide population-based study investigated the relationship between individual and neighborhood socioeconomic status (SES) and mortality rates for acute myocardial infarction (AMI) in Taiwan.

Methods: A population-based follow-up study included 23,568 patients diagnosed with AMI from 2004 to 2008. Each patient was monitored for 2 years, or until their death, whichever came first. The individual income-related insurance payment amount was used as a proxy measure of patient's individual SES. Neighborhood SES was defined by household income, and neighborhoods were grouped as advantaged or disadvantaged. The Cox proportional hazards model was used to compare the mortality rates between the different SES groups after adjusting for possible confounding risk factors.

Results: After adjusting for potential confounding factors, AMI patients with low individual SES had an increased risk of death than those with high individual SES who resided in advantaged neighborhoods. In contrast, the cumulative readmission rate from major adverse cardiovascular events did not differ significantly between the different individual and neighborhood SES groups. AMI patients with low individual SES had a lower rate of diagnostic angiography and subsequent percutaneous coronary intervention (P<0.001). The presence of congestive heart failure, chronic kidney disease, chronic obstructive pulmonary disease, pneumonia, septicemia, and shock revealed an incremental increase with worse SES (P<0.001).

Conclusions: The findings indicate that AMI patients with low individual SES have the greatest risk of short-term mortality despite being under a universal health-care system. Public health strategies and welfare policies must continue to focus on this vulnerable group.