Change in sedative burden after dementia onset using difference-in-difference estimations

Background Sedative agents are avoided in older adults because of potential risks including cognitive impairment, fall, frailty, and mortality. However, no studies addressing both prediagnostic and postdiagnostic period of dementia have evaluated sedative agent usage over an extended period. Objectives To describe a longitudinal change in sedative medication use before and after the diagnosis with dementia over 10 years compared to patients without dementia. Methods We conducted a retrospective cohort study using longitudinal claims data for senior national health insurance beneficiaries. After 1:4 propensity score matching, 54,165 older patients (60 years) were included. Difference-in-difference (DID) of sedative burden and use of sedative agents pre- and post-dementia diagnosis were estimated, and compared to those of patients without dementia. The yearly average daily sedative load (adSL) for each individual was calculated after applying duration, dose, and sedative score of medications from the sedative load model. The medication use for each sedative category was calculated using the defined daily dose (DDD) per 1000 patient-days. Results The adSL in patients with dementia was consistently high before and after diagnosis and significantly increased after diagnosis, compared to those of patients without dementia (DID 0.123 unit/day, 95% confidence interval 0.117–0.129). DID of medication use was the highest for antidepressants (64.764 DDD/1000 patient-days) followed by Z-drugs and antipsychotics. Atypical antipsychotic and antidepressant usage steeply increased after dementia diagnosis. Conclusion Sedative burden in patients with dementia before and after dementia diagnosis was higher than that in patients without dementia, and was further increased after dementia diagnosis.