Dementia Risk Higher for Stroke Survivors

TOPLINE:

Risk for dementia is nearly 80% higher in stroke survivors than in those without stroke, a new study reveals. The data suggest risk declines within 1 year after stroke but remains elevated for up to 20 years.

METHODOLOGY:

• Researchers conducted a population-wide analysis of over 15 million people in Canada between 2002 and 2022. The study focused on adults hospitalized for ischemic stroke, intracerebral hemorrhage, or acute myocardial infarction (AMI).
• Of 175,980 stroke survivors, 99% were matched 1:1 to residents without stroke on the basis of age, sex, rural residence, neighborhood deprivation, and vascular comorbidities. Additionally, 90% of patients were matched to those with AMI.
• Incident dementia diagnoses were tracked starting 90 days after stroke until death, emigration, or the end of the study, using a validated algorithm based on hospitalization for dementia, prescriptions for cholinesterase inhibitors, or physician claims within 2 years.
• The mean follow-up duration was 5.6 years.

TAKEAWAY:

• Among stroke survivors, 19% were diagnosed with dementia vs 12.5% in the reference population. The dementia rate per 100 person-years was higher among stroke survivors than in the reference population over the entire follow-up period (3.34 vs 1.89).
• Over the entire study period, dementia was 76% more likely among stroke patients (hazard ratio [HR], 1.76; 95% CI, 1.73-1.79) and 82% more likely in the AMI cohort (HR, 1.82; 95% CI, 1.79-1.85) than in the reference population.
• Time-varying analysis revealed that dementia risk was highest within the first year after stroke, with a > 2.5-fold increase at 6 months (HR, 2.51; 95% CI, 2.42-2.59), which decreased to a 1.5-fold increase at 5 years (HR, 1.51; 95% CI, 1.48-1.56) but remained elevated compared with the reference population even 20 years after the index stroke.
• Recurrent stroke was associated with an approximately threefold increased risk for dementia (single recurrent stroke adjusted HR, 2.64; 95% CI, 2.54-2.74; multiple recurrent strokes adjusted HR, 3.05; 95% CI, 2.81-3.33).

IN PRACTICE:

“While much research has been focused on reducing the risk of a second stroke, our findings make it clear that more research also is needed on developing interventions to help prevent dementia after stroke,” lead author Raed A. Joundi, MD, DPhil, McMaster University, Hamilton, Canada, said in a press release.

“There is a need to accelerate the implementation of promising interventions or multi-pronged approaches into large randomized controlled trials to lower the risk of dementia,” the investigators wrote.

SOURCE:

The study was published online on December 4 in Neurology.

LIMITATIONS:

The study’s limitations included reliance on administrative coding without imaging data, potential underestimation of mild dementia, and lack of granular information on stroke severity, disability, and prestroke cognitive decline. While adjustments were made for healthcare contact and secondary prevention medications, residual biases may have persisted.

DISCLOSURES:

This study received funding from the Canada Brain Research Fund, Heart & Stroke Foundation of Canada, and Canadian Stroke Consortium. Two authors hold awards and positions from national organizations and academic institutions in Canada. Additional details are provided in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.