Associations between empirical antimicrobial therapy at the hospital and mortality in patients with severe community-acquired pneumonia

Introduction. The aim of the study was to examine different antibiotic choices and their relation to outcomes. Methods. We reviewed patients with severe community-acquired pneumonia (SCAP) from two multicenter studies. Empirical antimicrobial regimens were classified as: macrolides alone (group M); macrolides plus betalactams (group MB); macrolides plus betalactam/betalactamase inhibitor (group MBI); every regimen including aminoglycosides (group A); non-pseudomonal third-generation cephalosporins alone (group C); another betalactam alone (first- and second-generation cephalosporins, or betalactam/betalactamase inhibitor) (group B); fluoroquinolones (group F); and other regimens (group Misc). Results. Initial distribution of regimens was: group MB: 261 patients; group A: 65 patients; group C: 31 patients; group B: 23 patients; group M: 18 patients; group MBI: 13 patients; group F: 11 patients; group Misc: 38 patients. The lowest overall mortality was associated with initial treatment with a macrolide plus other agent (or alone). No deaths were documented among the 13 patients receiving amoxicillin/clavulanate plus a macrolide. The excess mortality for initial treatment with group A was significantly higher (14.2%; CI 95% 27.3–1.1) than the overall mortality rate between patients receiving a macrolide plus other agents. No significant differences were documented when mortality was adjusted for intubated patients. Conclusion. Clinicians select the empirical antibiotic regimen after classifying patients according to likely pathogens and prognosis. The inclusion of a macrolide as part of the initial therapeutic regimen for SCAP appears to be as safe and effective as alternative options. Addition of a macrolide agent to a betalactam/betalactamase inhibitor or using a macrolide alone was a marker for less severe disease.