Dementia and Death After Stroke in Older Adults During a 10-year Follow-up: Results from a Competing Risk Model.

OBJECTIVES: To investigate the association between stroke and incident dementia in the presence of a competing risk of death.

METHODS: This study used the National Health Insurance Service-Senior (NHIS-Senior) claim database from 2002 to 2013 (n = 22,792). Stroke (I69.0-I69.9) and dementia (F01-F03, G30, G31.1) patients were defined by the International Classification of Disease 10th revision. The association of stroke with dementia or death was assessed with Cox proportional hazards model and competing-risk model.

RESULTS: During the 10-year follow-up period, there were 1,307 dementia events (5.7%) and 9,272 deaths (40.7%). In the Cox model, the adjusted hazard ratio (HR) for dementia was 2.37 times higher in those who experienced strokes, compared with the non-stroke group (95% CI: 2.23, 2.51). In the presence of death as competing event, stroke was associated with an elevated dementia incidence (HR = 2.06, 95% CI: 1.92, 2.20).

CONCLUSION: Stroke was significantly associated with an increased risk of incident dementia, with the magnitude of the association being attenuated in the competing risk model.