Background: Survival after acute myocardial infarction (AMI) varies with socioeconomic status. It is unknown whether these differences can be attributed, in part, to variations in the prevalence of atherogenic risk factors preceding the index AMI event.
Objectives: To examine how cardiovascular risk factors varied according to person-level indicators of income and education among a cohort of younger patients (younger than 65 years of age) hospitalized with AMI in Ontario.
Methods: The Socio-Economic and Acute Myocardial Infarction study (SESAMI) prospectively assembled a cohort of 3335 patients hospitalized with AMI who consented to participate (75% consent rate) from 53 of 57 large-volume institutions (100 AMI cases per year or more) throughout Ontario between December 1, 1999, and June 1, 2002. Given the known challenges inherent in characterizing the socioeconomic status in elderly patients and the ubiquity of atherosclerosis in elderly persons, the study focused on 1635 nonelderly participants. The relationship between income or education and cardiovascular risk factors, after adjustment for age, sex, ethnoracial factors and geography (urban-rural status) was examined.
Results: The prevalence of diabetes, hypertension, smoking and pre-existing heart disease was higher among poorer, less educated patients, as were the total number of cardiovascular risk factors. After adjusting for baseline factors, both income (adjusted OR 0.50, 95% CI 0.31 to 0.82, P=0.006) and education (adjusted OR 0.52, 95% CI 0.31 to 0.87, P=0.01) were independently associated with cardiovascular risk factors or pre-existing heart disease. There were no significant interactions between income, education and baseline cardiovascular risk.
Conclusions: Outcome differences across socioeconomic strata following AMI may reflect major income- and education-related differences in atherogenic risk profile.