The risk of developing dementia after stroke is 80% higher among individuals living with stroke vs the general population, according to the findings of a study published in Neurology.

Approximately half of stroke survivors develop significant cognitive dysfunction and more than a third of individuals who had a moderate or severe stroke develop dementia 1 year following a stroke.

A team of researchers from McMaster University and University of Toronto evaluated data from the Canadian Institutes for Health Information (CIHI) Discharge Abstract Database, Registered Persons Database (RPDB), Ontario Drug Benefits Database, and Physician Claims Database. Patients (n=175,980) who were admitted to the emergency department (ED) for acute stroke between 2002 and 2022 were matched with an individual admitted for acute myocardial infarction (AMI) or with an individual in the general population and evaluated for dementia onset through 2022.

The matched stroke-AMI cohorts comprised 151,673 individuals in each group and the stroke-reference cohorts comprised 174,817 in each group.

The risk was highest early after stroke but remained elevated 20 years after, highlighting the need for developing new interventions for dementia prevention in the acute and acute phases of stroke.

The stroke and AMI cohorts comprised 57.5% and 57.5% women, they were a mean age of 68.5 and 68.4 years at stroke or AMI, 76.0% and 75.8% had hypertension, and 33.6% and 32.6% had diabetes, respectively.

The stroke and reference cohorts comprised 69.3% and 69.3% women, they were a mean age of 69.3 and 69.3 years at stroke or inclusion, 77.5% and 77.5% had hypertension, and 33.2% and 33.2% had diabetes, respectively.

At 1 year, the rate of dementia was 4.79 per 100 person-years (py) vs 1.75 per 100 py in the stroke group compared with the reference population. At 5 years, the rates were 3.58 and 1.80 per 100 py in the stroke vs reference population, and at 10 years, the rates were 3.39 and 1.84 per 100 py, respectively.

Stratified by subgroups, the highest dementia incidence rate (IR) for the entire follow-up was observed among individuals with stroke aged 85 years and older (IR, 10.10 per 100 py) and the lowest was observed among the reference population aged 18 to 44 years (IR, 0.02 per 100 py).

Compared with the reference population, stroke survivors were at increased risk for dementia at 1 (hazard ratio [HR], 2.73), 5 (HR, 1.99), and 10 (HR, 1.83) years.

Stratified by type of stroke, individuals with ischemic stroke were at increased risk for dementia at 1(HR, 2.62), 5 (HR, 1.93), and 10 (HR, 1.78) years. Compared with the reference population, individuals with intracerebral hemorrhage (ICH) were at increased risk for dementia at 1 (HR, 4.19), 5 (HR, 2.75), and 10 (HR, 2.47) years.

Compared with AMI, stroke survivors were at increased risk for dementia at 1 (HR, 2.72), 5 (HR, 2.12), and 10 (HR, 1.92) years.

In the stroke and AMI cohorts, the cumulative incidence of dementia was twice that of recurrent stroke or stroke after AMI rates and the difference in rates became more pronounced over time.

This study may have missed some cases of mild dementia.

“The risk was highest early after stroke but remained elevated 20 years after, highlighting the need for developing new interventions for dementia prevention in the acute and acute phases of stroke,” the researchers concluded.

References:

Joundi RA, Fang J, Austin PC, et al. Magnitude and time-course of dementia risk in stroke survivors. Neurology. 2025;104(1):e210131. doi:10.1212/WNL.0000000000210131