Study Outcomes Among Patients with Parkinson’s Disease Treated for Psychosis Residing in the Long-Term Care Setting and Newly Initiating Pimavanserin or Off-Label Atypical Antipsychotics

Abstract

Introduction

Psychosis is a common feature of Parkinson’s Disease (PD), with an estimated 50% of PD patients experiencing psychosis (i.e., hallucinations [H] or delusions [D]) at some time during the course of their illness. Pimavanserin (PIM) is the only medication approved in the US for the treatment of H&D associated with Parkinson’s disease psychosis (PDP); however, off-label atypical antipsychotics (AAP) are continuously used. Currently, there are very few real-world studies which evaluate the patient characteristics and clinical outcomes among PD patients residing in the long-term care (LTC) setting within the US, newly initiated on PIM or other AAPs to treat psychosis.

Methods

A national LTC database consisting of diagnoses (DX), pharmacy orders (RX), and EHR data linked with the Minimum Data Set (MDS) was used to identify PD patients with a PD DX and 1 PD RX from 01/01/2017 to 09/30/2021 retrospectively. Patient groups were created: PIM group (patients with a PIM RX); AAP group (patients with an AAP RX [and no PIM RX]); and no treatment (No Tx) group (no PIM or AAP RX). All patients were required to have at least 100 days in LTC to be labelled as a resident (≤7 days between discharge and admission were included as LTC stay). Psychosis diagnosis was required at any time for the AAP and No Tx groups. Other medical causes of psychosis beyond PD were not excluded. The index dates were the first RX identified during the study time period for the PIM and AAP groups; and the psychosis DX date for the No Tx group. Incident treatment patients were defined as having no history of PIM or AAP in the 6 months prior to the index date. Patient/clinical characteristics, treatment patterns, and study outcomes were reported using means (SD) and frequencies during the post index period.

Results

There were: PIM group (N=3,120; N=870 incident), AAP group (N=5,880; N=2,396 incident), and No Tx group (N=1,802). The PIM and AAP groups had an average of 415 days and 383 days between the admitting date and the date of RX. The mean age among all groups was 76–77 years and 48–50% were female. PIM group patients were observed to be sicker with higher rates of concomitant dementia, depression, diabetes, and hypertension versus the AAP group or No Tx group. Initial treatments in the AAP group were mostly quetiapine (49%), risperidone (21%), or olanzapine (12%). The descriptive analysis during the 6 months post index showed the outcomes for the incident AAP group to have: higher proportion of falls and aggression events; higher incidence of new DX (physical changes, anxiety disorders, cognitive decline, insomnia, depression, and anticholinergic effects); and higher proportion of new medication orders (anticonvulsants, antidepressants, and benzodiazepines) compared with the incident PIM group.

Conclusions

In this descriptive LTC retrospective analysis, incident PIM patients were shown to have better outcomes versus the AAP group. These findings are subject to study limitations.

Funding

Acadia Pharmaceuticals Inc.