Purpose: Previous studies have documented increased risk of pneumonia with antipsychotic use in the elderly; however, differential risk across individual atypical antipsychotics remains unaddressed. This study examines the effect of individual atypical antipsychotics on risk of pneumonia in elderly patients.
Methods: This retrospective cohort study was conducted using a large claims database. The study population included new users of atypical antipsychotics (≥65 years). The multiple propensity-score adjusted survival model was used to examine risk of pneumonia within a 1-year follow-up period.
Results: A total of 92 234 patients newly prescribed atypical antipsychotic medication were identified. Of these, 41 780 (45.30%) were quetiapine users, 31 048 (33.66%) risperidone users, 11 375 (12.33%) olanzapine users, 6790 (7.36%) aripiprazole users, and 1241 (1.35%) ziprasidone users. Within the 1-year follow-up period, 12 411 (13.46%) patients taking atypical antipsychotics had a diagnosis of pneumonia. The multiple propensity-score-adjusted survival model revealed increased risk of pneumonia with the use of risperidone (hazard ratios (HR) 1.14, 95%CI 1.10-1.18) and olanzapine (HR 1.10, 95%CI 1.04-1.16) compared with the use of quetiapine.
Conclusion: This large population-based study suggests that use of risperidone and olanzapine increases risk of pneumonia compared with use of quetiapine in elderly patients. This study provides new information on the comparative risk of pneumonia associated with different atypical antipsychotics in the elderly to support optimal treatment decisions.
Keywords: atypical antipsychotics; comparative; elderly; multiple propensity scores; pharmacoepidemiology; pneumonia; risk; safety; second generation.
Copyright © 2015 John Wiley & Sons, Ltd.