Prevalence, incidence, and prognostic indicators of Dementia in patients with TIA and Stroke: the Population‐based Rotterdam Study

Abstract Background Risk of dementia is high after major stroke, but reliable estimates of dementia by stroke severity, accounting for competing risk of mortality, in a population‐based setting are scarce. In this study, we aimed to determine risk and prognostic indicators of dementia before and after TIA and stroke. Method We included all individuals with first‐ever TIA or stroke from the population‐based Rotterdam Study, between 2002‐2018, and matched those on age (+/‐3 years) and sex, using an incidence density sampling approach. We determined prevalence of pre‐event dementia by event severity (TIA vs. minor stroke [NIHSS≤3] vs. major stroke [NIHSS>3]). Similarly, we determined risk of dementia at 1‐,5‐ and 10‐year post‐event using the subdistribution hazards (SDH) cumulative incidence function (CIF), and explored prognostic indicators of dementia. Result Among 1352 participants with first‐ever TIA or stroke (mean age: 79.4 (9.5) years, 59.7% women), 466 had TIA, 392 minor stroke, 494 major stroke. Prevalence of pre‐event dementia was higher among patients with major stroke (90/494; 18.2%) than among those with minor stroke (29/392; 7.3%), TIA (37/466; 7.9%). During 10‐year follow‐up, dementia occurred in 784 of 4703 participants without pre‐event dementia or reference participants. Compared to TIA patients, dementia risk was higher after major stroke (HR 2.17; 95% CI 1.53–3.07) and minor stroke (HR 1.63; 95% CI 1.17–2.26). Dementia risk was associated with male sex (SDH‐ratio 1.23; 95% CI 1.04–1.45), age (per 1‐year increase: 1.07; 1.06–1.08), higher education (0.61; 0.44–0.86), diabetes mellitus (1.29; 1.06–1.56), atrial fibrillation (1.40; 1.14–.71), and premorbid cognition (MMSE≤24, 2.39; 1.87–3.05). Among 417 patients with available pre‐event brain MRI, white matter hyperintensity burden (per 1‐% increase of proportion of total brain volume: 1.24; 95% CI 1.07–1.45) and presence of microbleeds (2.14; 1.18–3.86) were indicators of post‐stroke dementia. Conclusion Dementia incidence after TIA and stroke is increased in patients with major stroke and to a lesser extent minor stroke, but not TIA. Event severity in combination with clinical and imaging indicators may hold potential for the prediction of cognitive decline after stroke.