Prevalence of Central Nervous System-Active Polypharmacy Among Older Adults With Dementia in the US.

Importance: Community-dwelling older adults with dementia have a high prevalence of psychotropic and opioid use. In these patients, central nervous system (CNS)-active polypharmacy may increase the risk for impaired cognition, fall-related injury, and death. Objective: To determine the extent of CNS-active polypharmacy among community-dwelling older adults with dementia in the US. Design, Setting, and Participants: Cross-sectional analysis of all community-dwelling older adults with dementia (identified by International Classification of Diseases, Ninth Revision, Clinical Modification or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnosis codes; N = 1 159 968) and traditional Medicare coverage from 2015 to 2017. Medication exposure was estimated using prescription fills between October 1, 2017, and December 31, 2018. Exposures: Part D coverage during the observation year (January 1-December 31, 2018). Main Outcomes and Measures: The primary outcome was the prevalence of CNS-active polypharmacy in 2018, defined as exposure to 3 or more medications for longer than 30 days consecutively from the following classes: antidepressants, antipsychotics, antiepileptics, benzodiazepines, nonbenzodiazepine benzodiazepine receptor agonist hypnotics, and opioids. Among those who met the criterion for polypharmacy, duration of exposure, number of distinct medications and classes prescribed, common class combinations, and the most commonly used CNS-active medications also were determined. Results: The study included 1 159 968 older adults with dementia (median age, 83.0 years [interquartile range {IQR}, 77.0-88.6 years]; 65.2% were female), of whom 13.9% (n = 161 412) met the criterion for CNS-active polypharmacy (32 139 610 polypharmacy-days of exposure). Those with CNS-active polypharmacy had a median age of 79.4 years (IQR, 74.0-85.5 years) and 71.2% were female. Among those who met the criterion for CNS-active polypharmacy, the median number of polypharmacy-days was 193 (IQR, 88-315 polypharmacy-days). Of those with CNS-active polypharmacy, 57.8% were exposed for longer than 180 days and 6.8% for 365 days; 29.4% were exposed to 5 or more medications and 5.2% were exposed to 5 or more medication classes. Ninety-two percent of polypharmacy-days included an antidepressant, 47.1% included an antipsychotic, and 40.7% included a benzodiazepine. The most common medication class combination included an antidepressant, an antiepileptic, and an antipsychotic (12.9% of polypharmacy-days). Gabapentin was the most common medication and was associated with 33.0% of polypharmacy-days. Conclusions and Relevance: In this cross-sectional analysis of Medicare claims data, 13.9% of older adults with dementia in 2018 filled prescriptions consistent with CNS-active polypharmacy. The lack of information on prescribing indications limits judgments about clinical appropriateness of medication combinations for individual patients.