Association of Socioeconomic Status With Ischemic Stroke Survival

Abstract

Background and Purpose— The aim of the study was to determine the impact of individuals’ socioeconomic status and their Primary Care Service Area Socioeconomic Index on survival after ischemic stroke. Methods— We conducted a nationwide population-based cohort study in Catalonia, Spain. We included all patients with first ischemic stroke admitted to a public hospital between January 1, 2015, and December 31, 2016. We measured both individual socioeconomic status (categorized as exempts, <€18 000 [$US 20 468] income per year, and >€18 000 income per year) and Primary Care Service Area Socioeconomic Index (from 0 to 100 categorized in quartiles). We used mixed-effects logistic and survival models to estimate odds ratios and hazard ratios for the short- (30 days) and the long-term (3 years) all-cause case fatality rates by individuals’ socioeconomic status groups. Results— The cohort consisted of 16 344 ischemic stroke patients with 24 638 person-years of follow-up. We did not find an association between the lowest socioeconomic individual status and short-term survival (odds ratio, 1.03; 95% CI, 0.76–1.40), although we found it in patients with <€18 000 income/year (odds ratio, 1.26; 95% CI, 1.10–1.45). At long-term, after adjustment, we observed a gradient in mortality risk with decreasing individual socioeconomic status (hazard ratio, 1.52; 95% CI, 1.30–1.77). The Primary Care Service Area Socioeconomic Index had only an influence on short-term survival (odds ratio, 1.19; 95% CI, 1.03–1.37). Conclusions— Individuals’ socioeconomic status was associated with short- and long-term survival in patients with ischemic stroke. Conversely, Primary Care Service Area Socioeconomic Index measures had an influence only in short-term survival. A small fraction of this association is due to differences in comorbidity and cardiovascular risk factors. Interventions addressing both individuals’ and primary care service socioeconomic aspects might eventually affect differently short- and long-term survival.