Depression, Type 2 Diabetes, and Poststroke Cognitive Impairment

Background Ten percent of stroke survivors develop dementia, which increases to more than a third after recurrent stroke. Other survivors develop less severe vascular cognitive impairment. In the general population, depression, and diabetes interact in predicting dementia risk, and they are both prevalent in stroke. Objective To assess the cumulative association of comorbid depressive symptoms and type 2 diabetes with cognitive outcomes among stroke survivors. Methods Multicenter observational cohort study of people within 6 months of stroke. Depression and cognitive status were screened using the Center for Epidemiological Studies Depression (CES-D) scale and the Montreal Cognitive Assessment (MoCA), respectively. Processing speed, executive function and memory were assessed using the Trail Making Test parts A and B, and the 5 Word Delayed Free Recall task. Results Among 342 participants (age 67.0 ± 13.5 years, 43.3% female, 46 ± 35 days poststroke), the prevalence of type 2 diabetes was 32.2% and depressive symptoms (CES-D ≥16) were found in 40.6%. Diabetes and depressive symptoms increased the risk of severe cognitive impairment (MoCA <20) with adjusted odds ratio (OR) 2.12 (95% confidence interval [CI] 1.20-3.74, P = .010) for 1 comorbidity and OR 3.18 (95% CI 1.26-8.02, P = .014) for both comorbidities. Associated cognitive deficits included executive function (F_{1, 168} = 3.43, P = .035) but not processing speed (F_{1, 168} = 1.86, P = .16) or memory (F_{1, 168} = 0.82, P = .44). Conclusions Diabetes and depressive symptoms were associated cumulatively with poorer cognitive screening outcomes poststroke, particularly deficits in executive function. Having 1 comorbidity doubled the odds of screening for severe cognitive impairment, having both tripled the odds.