Second-Generation Antipsychotic Medications and Risk of Pneumonia in Schizophrenia

This study assessed the association between second-generation antipsychotic medications and risk of pneumonia requiring hospitalization in patients with schizophrenia because the evidence is limited in the population. We enrolled a nationwide cohort of 33,024 inpatients with schizophrenia ranged in age from 18 to 65 years, who were derived from the National Health Insurance Research Database in Taiwan from 2000 to 2008. Cases (n = 1741) were defined as patients who developed pneumonia after their first psychiatric admissions. Risk set sampling was used to match each case with 4 controls by age, sex, and the year of the first admission based on nested case-control study. Antipsychotic exposure was categorized by type, duration, and daily dose, and the association between exposure and pneumonia was assessed using conditional logistic regression. We found that current use of clozapine (adjusted risk ratio = 3.18, 95% CI: 2.62-3.86, P < .001) was associated with a dose-dependent increase in the risk. Although quetiapine, olanzapine, zotepine, and risperidone were associated with increased risk, there was no clear dose-dependent relationship. Amisulpride was associated with a low risk of pneumonia. The use of clozapine combined with another drug (olanzapine, quetiapine, zotepine, risperidone, or amisulpride), as assessed separately, was associated with increased risk for pneumonia. In addition, with the exception of amisulpride, each drug was associated with increased risk for pneumonia at the beginning of treatment. Clinicians who prescribe clozapine to patients with schizophrenia should closely monitor them for pneumonia, particularly at the start of therapy and when clozapine is combined with other antipsychotics.