Associations Between Stroke Type, Ischemic Stroke Subtypes, and Poststroke Cognitive Trajectories

BACKGROUND: It is unclear how poststroke cognitive trajectories differ by stroke type and ischemic stroke subtype. We studied associations between stroke types (ischemic and hemorrhagic), ischemic stroke subtypes (cardioembolic, large artery atherosclerotic, lacunar/small vessel, and cryptogenic/other determined causes), and poststroke cognitive decline. METHODS: We pooled participants from 4 US cohort studies (1971–2019). Outcomes were change in global cognition (primary) and changes in executive function and memory (secondary). Outcomes were standardized as T scores (mean [SD], 50 [10]); a 1-point difference represents a 0.1 SD difference in cognition. The median follow-up for the primary outcome was 6.0 (interquartile range, 3.2–9.2) years. Linear mixed-effects models estimated changes in cognition after stroke. RESULTS: We identified 1143 dementia-free individuals with acute stroke during follow-up: 1061 (92.8%) ischemic, 82 (7.2%) hemorrhagic, 49.9% female, and 30.8% Black. The median age at stroke was 74.1 (interquartile range, 68.6–79.3) years. On average, ischemic stroke survivors showed declines in global cognition (−0.35 [95% CI, −0.43 to −0.27] points/y; P <0.001), executive function (−0.48 [95% CI, −0.59 to −0.36] points/y; P <0.001), and memory (−0.27 [95% CI, −0.36 to −0.19] points/y; P <0.001). Poststroke declines in global cognition, executive function, and memory did not differ between hemorrhagic and ischemic stroke survivors. Differences in poststroke cognitive slope between hemorrhagic and ischemic stroke survivors were global cognition (0.02 [95% CI, −0.21 to 0.26] points/y; P =0.85), executive function (−0.13 [95% CI, −0.48 to 0.23] points/y; P =0.48), and memory (0.19 [95% CI, −0.05 to 0.43] points/y; P =0.12). On average, small vessel stroke survivors showed declines in global cognition (−0.33 [95% CI, −0.49 to −0.16] points/y; P <0.001), executive function (−0.44 [95% CI, −0.68 to −0.19] points/y; P <0.001), and memory (−0.19 [95% CI, −0.35 to −0.03] points/y; P =0.02). Poststroke cognitive declines did not differ between small vessel survivors and survivors of other ischemic stroke subtypes. CONCLUSIONS: Stroke survivors had cognitive decline in multiple domains. Declines did not differ by stroke type or ischemic stroke subtype.