Incident stroke in patients with Alzheimer’s disease: A meta‐analysis

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AbstractBackgroundWe aimed to describe the risk of stroke in patients with Alzheimer´s disease (AD) and to compare it with matched controls without AD.MethodWe conducted a systematic review of all studies reporting incident stroke in AD patients according to the PRISMA guidelines. We included studies which: 1) reported ≥50 patients with a diagnosis of AD; 2) reported a retrospective or prospective follow‐up period; 3) specifically reported the occurrence of ischemic stroke and/or non‐traumatic ICH and/or stroke (all types) during the follow‐up period. We assessed the quality of studies using the Quality Assessment Tool for Observational Cohort and Cross‐Sectional Studies provided by the National Heart, Lung and Blood Institute. Using random effects meta‐analyses, we pooled the incidence rates and incidence rate ratios (IRR) of ischemic stroke, intracerebral hemorrhage (ICH) and stroke (all types) in AD patients.ResultTwenty‐nine (29) articles reporting incident ischemic stroke and/or incident ICH and/or incident stroke (all types) in patients with AD and were included in the meta‐analyses. The majority of studies was judged to have a fair quality. In patients with AD the incidence rates were 13.0 per 1000 person‐years for ischemic stroke, 3.4 per 1000 person‐years for ICH and 15.4 per 1000 person years for stroke (all types). When compared to matched controls without AD, incidence rate for ICH in AD patients was significantly higher (IRR 1.67, 95%CI 1.43‐1.96), but similar for ischemic stroke. Significant study heterogeneity was found in the meta‐analyses of incidence rates of ischemic stroke and stroke (all types) and moderate for studies reporting ICH.ConclusionIncident stroke is not a rare event in AD population. AD is associated with an increased risk of ICH which warrants further clarification. The significant risk of bias and heterogeneity among the studies, as well as the lack of information on possible confounding variables, does warrant the need for better quality studies on the overlap of the two neurological disorders with the highest disease burden worldwide.