Prescription characteristics associated with fall-related injury risk among older adults prescribed benzodiazepines: a cohort study

Abstract Background Benzodiazepines (BZD) are widely prescribed to older adults despite their association with increased fall injury. Our aim is to better characterize risk-elevating factors among those prescribed BZD. Methods A retrospective cohort study using a 20% sample of Medicare beneficiaries with Part D prescription drug coverage. Patients with a BZD prescription (“index”) between 1 April 2016 and 31 December 2017 contributed to incident (n=379,273) and continuing (n=509,634) cohorts based on prescriptions during a 6-month pre-index baseline. Exposures were index BZD average daily dose and days prescribed; baseline BZD medication possession ratio (MPR) (for the continuing cohort); and co-prescribed central nervous system-active medications. Outcome was a treated fall-related injury within 30 days post-index BZD, examined using Cox proportional hazards adjusting for demographic and clinical covariates and the dose prescribed. Results Among incident and continuing cohorts, 0.9% and 0.7% experienced fall injury within 30 days of index. In both cohorts, injury risk was elevated immediately post-index among those prescribed the lowest quantity: e.g., for