The impact of low income on long-term mortality of myocardial infarction patients: results from the Brazilian Heart Study

Abstract

Background Low socioeconomic status has for long been considered an important modifiable risk factor for developing cardiovascular disease, plausibly by lower access to healthcare, lower therapeutic adhesion, and overlapping of other known risk factors. Nevertheless, whether family income and social isolation of poor communities seen in Brazil impact outcomes following ST segment elevation myocardial infarction (STEMI) remain scarcely understood. Methods STEMI diagnosed patients were consecutively enrolled from the Brazilian Heart Study (ClinicalTrials.gov Identifier: NCT02062554) and categorized according to median family income (US$350), address-based human development index (HDI), and distance between communities and a tertiary hospital (DCTH). Incidence of death after 48 months was compared by using adjusted Cox regressions. p-values <0.05 were considered significant. Results Among 542 subjects, there were 69 deaths (13.2%) after a median follow-up time of 611 days (IQR =724). The low-income group had a higher incidence of all-cause mortality compared to high income (18.4 vs. 7.1%; p=.001), with an adjusted HR of 2.16 (95%CI: 1.25-3.75; p=.006). Compared to high income, low income individuals had worst clinical presentation of myocardial infarction and less frequently received dual antiplatelet therapy and statins at hospital discharge. Population attributable risk of low income was 44.8%. HDI and DCTH did not influence the delay to reperfusion therapy nor the risk of death. Conclusions Low-income was independently associated with a higher long-term mortality rate, lower prescription of guidelines-recommended therapy, and worst clinical presentation of myocardial infarction in STEMI patients.