Impact of Guideline-Concordant Empiric Antibiotic Therapy in Community-Acquired Pneumonia

Purpose: We evaluated the impact of guideline-concordant empiric antibiotic therapy on time to clinical stability, time to switch therapy, length of hospital stay, and mortality among patients with community-acquired pneumonia. Methods: This is a retrospective cohort study of all adult community-acquired pneumonia patients managed at 5 community hospitals from November 1, 1999 to April 30, 2000. Patients were stratified into guideline-concordant and discordant groups as defined by the 2001 American Thoracic Society and the 2003 Infectious Diseases Society of America guidelines. Time to clinical stability, time to switch therapy, length of hospital stay, and in-hospital mortality were evaluated in per-protocol and intention-to-treat stepwise regression models that included the outcome as the dependent variable, guideline-concordant antibiotic therapy as the independent variable, and Pneumonia Severity Index score as a covariate. Results: Of the 631 evaluable patients, 357 (57%) received guideline-concordant empiric antibiotic therapy. Groups were similar with respect to age, sex, comorbidities, severity of illness, and processes of care. Guideline-concordant antibiotic therapy was associated with a significant decrease in time to switch therapy (P ≤.01), length of hospital stay (P ≤.01), and in-hospital mortality (P = .04) for both per-protocol and intention-to-treat analyses. In addition, guideline-concordant antibiotic therapy was associated with a significant decrease in time to clinical stability for intention-to-treat analysis only (P = .03). Conclusions: Among hospitalized community-acquired patients, guideline-concordant antibiotic therapy is associated with improved in-hospital survival and shorter time to clinical stability, time to switch therapy, and length of hospital stay.