Falls and Fractures in Patients with Parkinson’s Disease-Related Psychosis Treated with Pimavanserin vs Atypical Antipsychotics: A Cohort Study

Abstract

Background: Parkinson’s disease-related psychosis increases patients’ risk of falls. Pimavanserin is an atypical antipsychotic approved in the USA in 2016 for the treatment of hallucinations and delusions associated with Parkinson’s disease-related psychosis. Objective: We aimed to compare the risk of falls/fractures among patients with Parkinson’s disease-related psychosis treated with pimavanserin vs other atypical antipsychotics. Patients and Methods: We identified a cohort of patients with Parkinson’s disease-related psychosis aged ≥ 40 years initiating either pimavanserin or a comparator antipsychotic (clozapine, quetiapine, risperidone, olanzapine, aripiprazole, brexpiprazole) in US commercial insurance and supplementary Medicare claims (2015–2019). Comparators were propensity score matched 2:1 with pimavanserin initiators; incidence rates of falls/fractures were compared using incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Results: We identified 112 eligible pimavanserin initiators and 982 comparators. Pimavanserin initiators were younger and had fewer severe comorbidities, indicators of impairment, and healthcare encounters, though they had higher Parkinson’s disease medication use. The crude incidence rates [cases/100 person-years] (95% CI) for composite falls/fractures were 17.8 (7.7–35.0) for pimavanserin and 40.8 (35.0–47.4) for comparators. Matching retained 108 pimavanserin initiators and 216 comparators—all characteristics were well balanced after matching—with a matched IRR (pimavanserin vs comparator) of 0.71 (95% CI 0.27–1.67). Sensitivity analysis IRR estimates were consistently below 1.00, with a sensitivity analysis not requiring a diagnosis of psychosis resulting in an IRR estimate of 0.55 (95% CI 0.34–0.86). Conclusions: The results of this study do not suggest an increase in the risk of falls or fractures associated with pimavanserin compared with other antipsychotics in patients with Parkinson’s disease-related psychosis. Sensitivity analyses suggest a decreased risk.