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

Abstract

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.

Figure.. Study Population of Older Adults With Dementia for Assessment of Central Nervous System (CNS)–Active Polypharmacy

^aFrom January 2015 to December 2017, persons had continuous Medicare Part A fee-for-service coverage (primarily covers inpatient and skilled nursing services) and Part B fee-for-service coverage (covers physician and outpatient services) but not Part C coverage (Medicare Advantage; beneficiaries enroll in a private health plan that delivers Medicare-covered Part A and Part B benefits). ^bThe Medicare Provider Analysis and Review file contains billing records (ie, claims) for inpatient care encounters (acute and skilled nursing). Outpatient encounters are captured in the carrier file (claims from noninstitutional clinicians such as physicians) and the outpatient file (claims for outpatient services from institutional clinicians, some of whom may also provide hospital services through Part A coverage). ^cA sensitivity analysis also was conducted that removed the 182 150 who died during 2018; among the 977 818 survivors, 142 602 experienced CNS-active polypharmacy (29 888 544 polypharmacy-days). Medicare beneficiaries do not have to enroll in Part D (prescription drug coverage) but in this study those without it were excluded (see prior box).