Improvement in clinical and economic outcomes with empiric antibiotic therapy covering atypical pathogens for community-acquired pneumonia patients: a multicenter cohort study

Objective: To determine the effectiveness of empiric antibiotic regimens covering atypical pathogens with respect to detailed clinical and economic outcomes in community-acquired pneumonia (CAP). Methods: A population-based, multicenter, retrospective cohort study was conducted from June 2010 to May 2011. Patients with a diagnosis of CAP were enrolled and categorized into two groups according to the initial antibiotic strategy used - covering or not covering atypical pathogens. Regression analysis was performed to assess their clinical outcomes (all-cause mortality, clinical improvement rate after 72 h of antimicrobial therapy, and clinical cure rate) and economic outcomes (length of stay, hospitalization costs, and antibiotic expenditure). Results: A total of 827 patients met the criteria for CAP; 561 (67.8%) received antibiotics with atypical pathogen coverage (APC group), while 266 (32.2%) did not (non-APC group). Regression analysis revealed that the all-cause mortality was much lower in the APC group than in the non-APC group (0.9% vs. 4.9%, respectively), with an odds ratio (OR) of 0.18 (95% confidence interval (CI) 0.06-0.49). Clinical improvement at 72 h (87.7% vs. 85.0%, p = 0.274) and the clinical cure rate (91.1% vs. 88.3%, p = 0.213) were more favorable in the APC group, but with no significant difference compared to the non-APC group. Moreover, the APC group had a shorter mean length of stay (APC 10.2 days vs. non-APC 11.6 days, p < 0.001). In addition, the mean total hospitalization costs for the APC group were markedly lower compared with the non-APC group (US$ 1172.7 vs. US$ 1510.7; p < 0.001). Conclusion: Antimicrobial treatment covering atypical pathogens for hospitalized CAP patients is associated with reduced mortality and economic burden. (C) 2015 Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.