Progression of cognitive and functional decline before and after stroke: evidence from four prospective cohort...

Previous studies had inconsistent results and often lacked pre-stroke cognitive assessments, hindering differentiation between stroke-related decline and normal ageing. To address this, we aimed to explore cognitive and functional change trajectories before and after stroke across countries.

This international population-based cohort study analyzed data from four nationally representative longitudinal studies across 23 countries: CHARLS, ELSA, HRS, and SHARE. A two-level growth model was used to estimate post-stroke cognitive trajectories, compared with those of stroke-free individuals.

69,013 participants from four longitudinal cohorts were included and 2,106 participants had their first-ever stroke. Compared with stroke-free participants, stroke patients had faster pre-stroke cognitive decline, with adjusted differences in annual decline ranging from - 0.033 to - 0.049 SD/y across cognitive domains. Stroke correlated with an acute global cognitive drop (pooled β = - 0.319 [95% CI - 0.467 to - 0.276]) and accelerated subsequent decline (pooled β = -0.039 SD/y). Post-stroke declines in memory (- 0.015 SD/y), orientation (- 0.033 SD/y), and executive function (- 0.004 SD/y) were observed. Recurrent stroke linked to worse post-stroke decline; exclusion of these cases reduced estimated acute and pre-stroke decline by 23.05% and 13.79%, respectively. In stroke-free individuals, vascular risk factors and social isolation correlated with steeper cognitive decline, consistent across European, North American and Asian cohorts.

Our findings demonstrate that stroke links to acute reduction and ongoing accelerated decline in cognitive/functional abilities, starting pre-stroke and continuing post-stroke. This underscores the need to include multidimensional outcome measures in stroke care and emphasizes prioritizing cognitive health in stroke prevention and post-stroke management.