OBJECTIVES: Psychosis occurs in about 60% of patients with Parkinson’s disease (PD) and is usually treated with antipsychotics (AP). However, AP use in PD may worsen patients’ motor symptoms which may lead to pneumonia. The study assessed whether there was an increased risk of pneumonia among PD patients receiving antipsychotic therapy.

METHODS: This study was conducted using the 2014-2016 5% national Medicare administrative claims data. Beneficiaries aged ≥65 with a diagnosis of PD in 2014-2015 were identified. Those with a diagnosis of secondary parkinsonism, dementia with Lewy bodies, schizophrenia and bipolar disorder were excluded. Incident AP users were identified and matched with non-users on propensity scores calculated using sex, age, race, disease severity, diagnosis for dementia, delirium and psychosis. Covariate balance was assessed using absolute standardized differences. The first date of incident AP use was identified as index date for users and assigned to their corresponding matched non-users. Beneficiaries were followed from index date till the occurrence of pneumonia or the end of study period (2016), whichever occurred first. Cox proportional hazards regression was used to assess the association between AP use and pneumonia.

RESULTS: A total of 18234 PD patients were identified, among them, 639 were incident AP users. After propensity score matching, 637 pairs of users and non-users were included for analysis. Most AP users were male (53%), White (94%), had mild-to-moderate PD (87%) with mean age 77.9(±7.9) years. There was no statistically significant evidence for increased risk of pneumonia with AP use (HR = 1.07, 95% CI: 0.81 – 1.42) among PD patients.

CONCLUSIONS: This study shows that AP use is not associated with an increased risk of pneumonia among PD patients, however, there may be other confounders not captured in our study. Further research should consider other comorbidities to better understand the association between AP use and pneumonia.