Socioeconomic risk factor aggregation and long-term incidence of ischemic stroke in patients after first acute myocardial infarction

Background: Low socioeconomic status (SES) has been associated with increased cardiovascular risk. However, the association between SES and stroke incidence in patients with acute myocardial infarction (AMI) has not been studied. We assessed the association between a multidimensional SES construct and long-term ischemic stroke incidence after AMI in a prospective community-based cohort study. Methods: A total of 1261 consecutive patients aged ≤ 65 years discharged after first AMI from 8 hospitals in central Israel in 1992-1993 were followed for ischemic stroke for a mean (SD) period of 11 (4) years. The number of unfavorable SES factors, including lower than average family income, ≤ 8 years of education, unemployment, and absence of a steady partner, was the primary exposure. We estimated the directly adjusted cumulative incidence of stroke treating non-stroke death as a competing event using the Fine and Gray model for a subdistribution function. Results: Low SES was associated with older age, female sex, higher risk factor prevalence, increased AMI severity and inferior treatment. Ischemic stroke was diagnosed in 142 patients. The adjusted cumulative incidence of ischemic stroke gradually increased with the number of unfavorable SES factors. The multivariable adjusted HRs (95% confidence intervals) for ischemic stroke were 1.5(0.9-2.4), 2.0(1.2-3.2) and 2.1(1.2-3.6) in patients with 1, 2 and ≥ 3 unfavorable SES factors respectively, compared with those with none. Conclusions: Our data support a dose-response relationship between SES and stroke risk after AMI and suggest a multidimensional vulnerability related to SES. These findings should be considered in planning secondary prevention strategies post-AMI.