(P-604) Risk of Hospitalization and Death Associated with Pimavanserin Use in Older Adults with Parkinson’s Disease

Background: Pimavanserin is a novel antipsychotic approved in 2016 by the US Food and Drug Administration for management of psychotic symptoms in patients with Parkinson’s disease.

Objectives: To evaluate the risk of hospitalization and death associated with pimavanserin use.

Methods: This retrospective cohort study was conducted from November 1, 2015 through December 31, 2018 using an administrative dataset on residents of Medicare-certified long-term care facilities that were linked with Medicare claims data. Long-term care residents aged 65 years and older with Parkinson’s disease were included. The primary exposure was pimavanserin use vs nonuse. Propensity score-based inverse probability of treatment weighting was used to balance pimavanserin users and nonusers on baseline characteristics including demographics, comorbidities, and concomitant medication use. Up to one year of follow-up was observed. Inverse probability of treatment weighted Fine-Gray competing risk and Cox proportional hazards regression models were used to estimate the risk of hospitalization and death, respectively.

Results: The study cohort included 2186 pimavanserin users and 18 212 nonusers. There was a higher risk of 30-day hospitalization with pimavanserin use vs nonuse (rate per 100 person-years, 151 vs 110; IPTW adjusted hazard ratio [aHR] 1.24; 95% confidence intervals [CI] 1.06-1.43). There was no association of pimavanserin use with 90-day hospitalization (aHR 1.10; CI 0.99-1.24) nor with 30-day mortality (aHR 0.76; CI 0.56-1.03). Pimavanserin use vs nonuse was associated with an increased 90-day mortality (rate per 100 person-years, 46 vs 40; aHR 1.20; CI 1.02-1.41) that persisted after 180 days (rate per 100 person-years, 48 vs 39; aHR 1.28; CI 1.13-1.45) and 1 year (rate per 100 person-years, 58 vs 39; aHR 1.56; CI 1.42-1.72).

Conclusions: Pimavanserin use vs nonuse in older adults was associated with an increased risk of hospitalization at one month of initiation and a higher risk of death for up to one year following initiation. These findings, in a large real-world cohort within long-term care facilities, may help to inform decisions regarding its risk-benefit balance among patients with Parkinson’s disease.