Comparison of Pimavanserin Versus Quetiapine for Hospitalization and Mortality Risk Among Medicare Beneficiaries with Parkinson's Disease Psychosis.

Background: Pimavanserin is currently the only antipsychotic approved for Parkinson's disease (PD) psychosis, yet its relative safety compared with treatment alternatives has not been thoroughly assessed.

Objectives: This study aimed to compare hospitalization and mortality risk in Medicare beneficiaries with PD receiving new prescriptions of pimavanserin or quetiapine for PD psychosis.

Methods: The study identified new users of pimavanserin and quetiapine from a 15% national sample of Medicare fee-for-service claims collected between May 1, 2016, and December 30, 2018. All-cause hospitalization and mortality were assessed in time-to-event regression models. Standardized mortality ratio weighting balanced pimavanserin and quetiapine users on baseline characteristics. Follow-up was censored at discontinuation, switch, disenrollment, or the end of the study period.

Results: There were 844 new pimavanserin users and 2505 new quetiapine users. The adjusted hazard ratios (95% confidence intervals [CIs]) for hospitalization at 30, 90, 180, and 365 days for pimavanserin versus quetiapine users were 0.59 (0.43-0.81), 0.56 (0.44-0.72), 0.63 (0.52-0.77), and 0.70 (0.60-0.83). The most common reasons for hospitalization were traumatic injury and sepsis. Hospitalizations for heart-related issues were higher with pimavanserin ( < 0.05). The adjusted hazard ratios (95% CIs) for all-cause mortality at 90, 180, and 365 days for pimavanserin versus quetiapine users were 0.73 (0.48-1.13), 0.80 (0.58-1.10), and 0.94 (0.74-1.19).

Conclusions: Risk of hospitalization was lower in pimavanserin users compared with quetiapine, and no difference in mortality was observed between pimavanserin and quetiapine. An active comparator analyses with treatment alternatives provided the most clinically relevant information for patients and physicians.