Antipsychotic drug use and pneumonia: Systematic review and meta-analysis

Objectives: The purpose of this study was to investigate the association of antipsychotic exposure to the incidence and mortality of pneumonia. Methods: The design of this study involved meta-analysis of observational studies identified from electronic databases. Results: In total, 19 studies were included in the systematic review and 14 in the meta-analysis. Risk of pneumonia was increased by first-generation antipsychotics (risk ratio 1.69, 95% confidence interval 1.34-2.15; five studies), second-generation antipsychotics (risk ratio 1.93, 95% confidence interval 1.55-2.41; six studies) and all antipsychotics (risk ratio 1.83, 95% confidence interval 1.60-2.10; seven studies) compared with no antipsychotic use. Pneumonia risk did not differ in seven studies comparing first-generation antipsychotics with second-generation antipsychotics (risk ratio 1.07, 95% confidence interval 0.85-1.35). Case fatality rate was not different in pneumonia cases associated with antipsychotic exposure versus cases without exposure (risk ratio 1.50; 95% confidence interval 0.76-2.96; two studies). All antipsychotics with data from 2 studies allowing meta-analysis, were associated with a significantly increased pneumonia risk (i.e. haloperidol, olanzapine, clozapine, risperidone, quetiapine, zotepine). Conclusion: Exposure to both first-generation antipsychotics and second-generation antipsychotics is associated with an increased pneumonia risk. Clinicians need to be vigilant for the occurrence of pneumonia in patients commencing antipsychotics, especially those with other risk factors for pneumonia including older age, chronic respiratory disease, cerebrovascular disease, dysphagia and smoking.