Cardiovascular disease and the risk of dementia: a survival analysis using administrative data from Manitoba.

Objectives: Recent research has shown that cardiovascular disease (CVD) raises the risk of dementia and other forms of cognitive decline. Generally, these studies are unable to model the time of diagnosis of CVD in their analyses and treat CVD as a time-fixed variable. Our objective was to assess the risk of being diagnosed with dementia for individuals diagnosed with CVD when CVD is time-dependent.

Methods: We performed a retrospective cohort study using administrative health datasets from the Manitoba Population Research Data Repository in Canada. We constructed a longitudinal dataset to track individuals enrolled in the Manitoba Health Insurance Registry between April 1, 1997 and March 31, 2015. The study population consisted of 496,192 individuals 30 years of age or older who were not diagnosed with CVD or dementia prior to April 1, 1997. Diagnoses of CVD and dementia were based on diagnosis codes from medical claims and hospitalizations and the use of prescription medications. Hazard ratios were then computed using adjusted Cox-proportional hazards analyses.

Results: Among the CVD subgroups considered, atrial fibrillation, ischemic heart disease, and stroke increased the risk of developing dementia, with stroke doubling one's risk of being diagnosed with the disease (hazard ratio: 1.95; 95% confidence interval: 1.9, 2.01). Age, lower socioeconomic status, and worsening comorbidities also increased the risk of being diagnosed with dementia.

Conclusion: A diagnosis of CVD is associated with an increased risk of a future diagnosis of dementia. Promoting good cardiovascular health may serve as an effective measure for preventing dementia.