Risk of pneumonia associated with atypical antipsychotic use in nursing home residents with Parkinson's disease.

According to the American Geriatrics Society (AGS) Beers criteria, most atypical antipsychotic (AAPs) are inappropriate in patients with Parkinson's disease (PD) due to the risk of worsening Parkinsonian symptoms. This study evaluated the risk of pneumonia associated with inappropriate AAP use in elderly nursing home residents with PD. The study population encompassed older adults aged 65 years or older with a diagnosis of PD and with comorbid depression who started the AAP medication. Appropriate AAPs were defined as aripiprazole, clozapine or quetiapine according to 2015 Beers criteria, and inappropriate AAPs included olanzapine, asenapine, brexpiprazole, iloperidone, lurasidone, paliperidone, risperidone, or ziprasidone. Cox regression analyses involved propensity score-matched users of inappropriate and appropriate AAPs to examine the association between AAP use and risk of pneumonia. The mean age of patients in propensity-matched cohort (n = 12,076) was 82.15 years (SD = 6.97). The pneumonia incidence rates were 37.19 and 45.92 per person-year in appropriate and inappropriate AAP groups, respectively. Multivariable Cox regression analyses revealed increased risk of pneumonia [Hazard Ratio (HR) 1.20 (1.08-1.34)] for nursing home residents who were taking inappropriate compared to those taking appropriate AAP. In sensitivity analyses, the pneumonia risk was 1.28 (1.12-1.47) for risperidone vs. quetiapine and 1.29 (1.06-1.57) for olanzapine vs. quetiapine. The risk of pneumonia was significantly higher for patients with PD who used inappropriate AAP in comparison to appropriate AAP group in all analyses. This investigation warrants further attention regarding safety of atypical antipsychotics in PD.