Incidence of Dementia Among Medicare Beneficiaries With and Without Urinary Incontinence

IMPORTANCE: Dementia and urinary incontinence (UI) have been associated in cross-sectional studies. The temporal relationship between these 2 conditions is not well understood. OBJECTIVE: The aim of the study was to investigate the risk of incident dementia in female adults with and without UI using the Medicare 5% Limited Data Set. STUDY DESIGN: This retrospective cohort study matched females with UI to continent controls by index year, age, and dual Medicare/Medicaid eligibility. A 2-year look back period was used to exclude prevalent dementia and neurologic disorders. The 5-year cumulative incidence of dementia was estimated for women with UI and controls. Cox proportional hazard models assessed the association of variables with dementia, adjusting for age, dual Medicare/Medicaid eligibility, race, and comorbidities. RESULTS: A total of 8,651 female beneficiaries with UI (n = 8,651) were more likely than matched controls (n = 8,651) to report White race and several medical comorbidities. The 5-year cumulative incidence of dementia diagnosis was lower in the UI versus controls (8.8% vs 10.6%, P  < 0.001). In multivariable analysis with adjustment for covariates, UI diagnosis was associated with a lower hazard of dementia diagnosis (hazard ratio 0.82 [0.74, 0.91], P  < 0.001). CONCLUSIONS: Among female Medicare beneficiaries without baseline neurologic disorders, having any UI diagnosis was associated with a lower risk of dementia diagnosis. Further studies assessing UI symptoms and dementia diagnosis with rigorous and valid assessment tools are needed to confirm this finding.