A hypothesis-generating study of the combination of aspirin plus macrolides in patients with severe community-acquired pneumonia

Abstract

While the inflammatory response to severe pneumonia is paramount in limiting and resolving the infection, excessive inflammation can lead to deleterious effects. We theorized that patients with severe community-acquired pneumonia (CAP) who were treated with macrolides and aspirin would receive benefit beyond that of conventional antibiotic therapy. An observational study was conducted with patients with severe CAP. All patients were admitted to 5 teaching hospitals (in Italy, the United States, Japan, and China), and data were gathered from their electronic medical records. Severe pneumonia was defined according to Infectious Diseases Society of America/American Thoracic Society criteria. Patients were divided into 4 groups, i.e., (i) the aspirin-only group (ASG), (ii) the macrolide-only group (MG), (iii) the aspirin plus macrolide group (ASMG), or (iv) the neither aspirin nor macrolide group (NASMG). Survival rates for the 4 groups were evaluated after adjustment for confounders and after weighting by propensity score. A total of 1,295 patients were included in the analysis. There were 237 patients (18.3%) in the ASG, 294 (22.7%) in the MG, 148 (11.4%) in the ASMG, and 616 (47.6%) in the NASMG. The mortality rate at 30 days was 15.5% in the ASMG, compared to 28.2% in the NASMG, 23.8% in the MG, and 21.1% in the ASG. After propensity score analysis, receipt of aspirin plus macrolide (hazard ratio, 0.71 [95% confidence interval, 0.58 to 0.88]; P 0.002) was associated with a higher 30-day survival rate. This is a hypothesis-generating study in which data suggest that the combination of aspirin plus a macrolide improves 30-day survival rates for patients with severe CAP. Further randomized studies will need to be undertaken to confirm this phenomenon.