Longitudinal Associations of Stroke With Cognitive Impairment Among Older Adults in the United States: A Population-Based Study

Moderating Effects of Informal Care on the Relationship Between ADL Limitations and Adverse Outcomes in Stroke Survivors

BACKGROUND

Stroke survivors with limitations in activities of daily living (ADL) have a greater risk of experiencing falls, hospitalizations, or physical function decline. We examined how informal caregiving received in hours per week by stroke survivors moderated the relationship between ADL limitations and adverse outcomes.

METHODS

In this retrospective cohort, community-dwelling participants were extracted from the National Health and Aging Trends Study (2011-2020; n=277) and included if they had at least 1 formal or informal caregiver and reported an incident stroke in the prior year. Participants reported the amount of informal caregiving received in the month prior (low [<5.8], moderate [5.8-27.1], and high [27.2-350.4] hours per week) and their number of ADL limitations (ranging from 0 to 7). Participants were surveyed 1 year later to determine the number of adverse outcomes (ie, falls, hospitalizations, and physical function decline) experienced over the year. Poisson regression coefficients were converted to average marginal effects and estimated the moderating effects of informal caregiving hours per week on the relationship between ADL limitations and adverse outcomes.

RESULTS

Stroke survivors were 69.7% White, 54.5% female, with an average age of 80.5 (SD, 7.6) years and 1.2 adverse outcomes at 2 years after the incident stroke. The relationships between informal caregiving hours and adverse outcomes and between ADL limitations and adverse outcomes were positive. The interaction between informal caregiving hours per week and ADL limitations indicated that those who received the lowest amount of informal caregiving had a rate of 0.12 more adverse outcomes per ADL (average marginal effect, 0.12 [95% CI, 0.005-0.23]; P=0.041) than those who received the highest amounts.

CONCLUSIONS

Informal caregiving hours moderated the relationship between ADL limitations and adverse outcomes in this sample of community-based stroke survivors. Higher amounts relative to lower amounts of informal caregiving hours per week may be protective by decreasing the rate of adverse outcomes per ADL limitation.

Cognitive Impairment Is Associated with New-Onset Stroke: Evidence from a Nationwide Prospective Cohort Study

INTRODUCTION

Stroke is closely related to cognitive function, and many patients experience cognitive impairment after stroke; however, whether cognitive impairment is associated with an increased risk of stroke remains inconclusive. This study aims to investigate whether cognitive impairment is associated with new-onset stroke (first ever nonfatal stroke) using a national prospective study.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018 were used. A total of 11,961 Chinese participants aged ≥45 years without a history of stroke were included in the present study and divided into a cognitive impairment group and a normal group according to the baseline cognitive score. Logistic regression analysis was used to analyse the association between baseline cognitive function and new-onset stroke.

RESULTS

During the 6.96-year follow-up period, 875 participants experienced new-onset stroke. Compared with the cognitively normal group, the odds ratio (95% confidence intervals) for new-onset stroke in the cognitively impaired group was 1.21 (1.04, 1.40) when not adjusted for confounders and 1.22 (1.01, 1.48) after adjusting for established confounding factors, including demographic data, medical history, physical examination, and laboratory indicators.

CONCLUSION

Cognitive impairment was associated with new-onset stroke among middle-aged and elderly Chinese individuals. Further studies should be carried out to confirm the causal relationship between cognitive impairment and stroke.

Longitudinal Brain Changes After Stroke and the Association With Cognitive Decline

Background

Cognitive impairment is common after stroke. So is cortical- and subcortical atrophy, with studies reporting more atrophy in the ipsilesional hemisphere than the contralesional hemisphere. The current study aimed to investigate the longitudinal associations between (I) lateralization of brain atrophy and stroke hemisphere, and (II) cognitive impairment and brain atrophy after stroke. We expected to find that (I) cortical thickness and hippocampal-, thalamic-, and caudate nucleus volumes declined more in the ipsilesional than the contralesional hemisphere up to 36 months after stroke. Furthermore, we predicted that (II) cognitive decline was associated with greater stroke volumes, and with greater cortical thickness and subcortical structural volume atrophy across the 36 months.

Methods

Stroke survivors from five Norwegian hospitals were included from the multisite-prospective “Norwegian Cognitive Impairment After Stroke” (Nor-COAST) study. Analyses were run with clinical, neuropsychological and structural magnetic resonance imaging (MRI) data from baseline, 18- and 36 months. Cortical thicknesses and subcortical volumes were obtained via FreeSurfer segmentations and stroke lesion volumes were semi-automatically derived using ITK-SNAP. Cognition was measured using MoCA.

Results

Findings from 244 stroke survivors [age = 72.2 (11.3) years, women = 55.7%, stroke severity NIHSS = 4.9 (5.0)] were included at baseline. Of these, 145 (59.4%) had an MRI scan at 18 months and 72 (49.7% of 18 months) at 36 months. Most cortices and subcortices showed a higher ipsi- compared to contralesional atrophy rate, with the effect being more prominent in the right hemisphere. Next, greater degrees of atrophy particularly in the medial temporal lobe after left-sided strokes and larger stroke lesion volumes after right-sided strokes were associated with cognitive decline over time.

Conclusion

Atrophy in the ipsilesional hemisphere was greater than in the contralesional hemisphere over time. This effect was found to be more prominent in the right hemisphere, pointing to a possible higher resilience to stroke of the left hemisphere. Lastly, greater atrophy of the cortex and subcortex, as well as larger stroke volume, were associated with worse cognition over time and should be included in risk assessments of cognitive decline after stroke.