Changes in Medication Use After Dementia Diagnosis in an Observational Cohort of Individuals with Diabetes Mellitus.

OBJECTIVES: To assess changes in medication use after a diagnosis of dementia in individuals with type 2 diabetes mellitus.

DESIGN: Difference-in-differences analysis of changes in the number of dispensed chronic medications between individuals with and without newly diagnosed dementia.

SETTING: Integrated healthcare delivery system, Kaiser Permanente Northern California.

PARTICIPANTS: Individuals aged 50 and older without prevalent dementia with type 2 diabetes mellitus enrolled in a baseline survey. During 5 years of follow-up, 193 individuals with a new diagnosis of dementia were identified, and risk-set sampling was used to randomly select five reference subjects per case matched on 5-year age categories and sex (965 matched participants), resulting in an analytical sample of 1,158.

MEASUREMENTS: The exposure was new diagnosis of dementia. The primary outcome was change in number of current chronic medications (total, cardiovascular (blood pressure and lipid control), diabetes mellitus) at three times: 1 year before index date (preindex date), date of diagnosis of dementia or matched reference date (index date), and up to 1 year after index date or end of follow-up if censored before 1 year (postindex date).

RESULTS: After adjustment, the number of chronic medications and the subset of cardiovascular medications declined after a dementia diagnosis in the overall cohort and in age-, sex-, and time-matched reference individuals, but the decline was significantly greater in the group with dementia (0.71 medications fewer than the reference group, P = .02). The number of diabetes mellitus medications declined in both groups, but the declines were not statistically different (0.18 medications fewer than the reference group, P = .008).

CONCLUSIONS: Use of cardiometabolic medications fell after a diagnosis of dementia, as recommended in national guidelines.