RISK OF HOSPITALIZATION FOR PNEUMONIA ASSOCIATED WITH THE USE OF ATYPICAL VERSUS TYPICAL ANTIPSYCHOTICS IN A NATIONAL SAMPLE OF MEDICARE BENEFICIARIES

OBJECTIVES: To evaluate the risk of hospitalization for pneumonia associated with typical and atypical antipsychotic use in an elderly Medicare population. METHODS: This retrospective cohort study used two years (2006-2007) of 5% national sample of Medicare claims data. Medicare beneficiaries with continuous Part A, B, and D enrollment in 2006-2007 and who initiated atypical or typical antipsychotic drug therapy during July 2006-June 2007 were identified from Part D claims data. Propensity score matching was used to control for potential confounding. A conditional logistic regression model stratified on propensity score-matched pair was used to compare the risk of hospitalization for pneumonia in new users of atypical vs. typical antipsychotic drugs within a 180 day follow-up period starting from the date of first prescription. RESULTS: A total of 15,637 new users of atypical and 2,337 new users of typical antipsychotic drugs were identified July 2006-June 2007. A total of 1,363(7.6%) subjects had a hospitalization for pneumonia during follow-up. The proportion of hospitalizations was similar in the atypical (7.5%) and the typical antipsychotic (8.0%) groups. A total of 2,335 propensity score-matched pairs were obtained using the Greedy 5-1 matching algorithm. In the matched cohort, there were 186 (7.97%) pneumonia hospitalizations in typical users compared to 179 (7.67%) among atypical users. Typical antipsychotics users did not differ significantly from atypical users on the risk of pneumonia (odds ratio: 1.042, 95% CI: 0.843-1.288). Sensitivity analysis using propensity score as a continuous variable in a multivariable logistic regression model yielded similar results (odds ratio: 0.976, 95% CI: 0.828-1.150). CONCLUSIONS: The risk of hospitalization for pneumonia was similar for new users of typical and atypical antipsychotic drugs. While this indicates that there is no added safety concern for users of atypical antipsychotics, it also suggests there is no added advantage of atypical use, especially in patients at high risk for pneumonia.