Author Response: Risk of Hospitalization and Death Associated With Pimavanserin Use in Older Adults With Parkinson Disease

BACKGROUND AND OBJECTIVES:To determine the risk of hospitalization and death associated with pimavanserin use. METHODS:We conducted a retrospective cohort study of adults 65 years and older with Parkinson disease between November 1, 2015, and December 31, 2018, using an administrative dataset on residents of Medicare-certified long-term care facilities and linked Medicare claims data. Propensity score-based inverse probability of treatment weighting (IPTW) was used to balance pimavanserin users and nonusers on 24 baseline characteristics. Fine-Gray competing risk and Cox proportional hazards regression models were used to estimate the risk of hospitalization and death up to 1 year, respectively. RESULTS:The study cohort included 2,186 pimavanserin users and 18,212 nonusers. There was a higher risk of 30-day hospitalization with pimavanserin use vs nonuse (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) or with 30-day mortality (aHR 0.76, CI 0.56-1.03). Pimavanserin use vs nonuse was associated with increased 90-day mortality (aHR 1.20, CI 1.02-1.41) that persisted after 180 days (aHR 1.28, CI 1.13-1.45) and 1 year (aHR 1.56, CI 1.42-1.72). DISCUSSION:Pimavanserin use vs nonuse in older adults was associated with an increased risk of hospitalization at 1 month of initiation and a higher risk of death for up to 1 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 disease. CLASSIFICATION OF EVIDENCE:This study provides Class II evidence that in patients with Parkinson disease who are 65 or older and residing in Medicare-certified long-term care facilities, pimavanserin is associated with an increased risk of 30-day hospitalization and higher 90-, 180-, and 365-day mortality.