Socioeconomic Disparities in Rate of Poststroke Dementia: A Nationwide Cohort Study

BACKGROUND: Socioeconomic disparities exist in acute stroke care as well as in long-term stroke outcomes. We aimed to investigate whether socioeconomic status was associated with the rate of poststroke dementia (PSD). METHODS: This was a nationwide register-based cohort study including all patients with incident ischemic or hemorrhagic stroke in Denmark from 2010 to 2020. Socioeconomic status was defined by prestroke income, education, and employment. PSD was defined as a dementia diagnosis in the National Patient Registry or a dispensed prescription of dementia medication after a stroke. PSD incidence rates were compared between socioeconomic status groups using Poisson regression. RESULTS: A total of 98 489 patients with incident stroke without a diagnosis of prestroke dementia were identified and followed for a median (IQR) of 4.2 (IQR, 2.1–7.3) years. Median age was 72 (62–80) years, 56% were male, 5.1% were immigrants, and 86% had ischemic stroke. Dementia was diagnosed in 5680 patients at a median of 2.4 (IQR, 0.9–4.8) years after stroke (incidence rate=12.1/1000 person-years). After adjusting for age, sex, and immigrant status, PSD rates were 1.24 (1.15–1.34) times higher for low income compared with high income, 1.11 (1.03–1.20) times higher for low education compared with high education, and 1.57 (1.38–1.77) times higher for patients without employment compared with patients with employment. Further adjustments for stroke severity, cohabitation, and comorbidities showed similar results. Stratified analyses showed that the socioeconomic disparities in PSD rates were more pronounced among women, immigrants, and patients <70 years of age. CONCLUSIONS: Low socioeconomic status measured by prestroke income, education, and employment status was associated with higher rates of PSD. These socioeconomic disparities extended beyond what could be explained by common PSD risk factors.