Effects of guideline-concordant antimicrobial therapy on mortality among patients with community-acquired pneumonia

National practice guidelines have recommended specific initial empiric antimicrobial regimens for patients with community-acquired pneumonia. Our aim was to determine the association between the use of guideline-concordant antimicrobial therapy and 30-day mortality in patients with pneumonia. We conducted a retrospective cohort study at two tertiary teaching hospitals. Eligible patients were admitted with a diagnosis of community-acquired pneumonia, had a chest radiograph consistent with pneumonia, and had a discharge diagnosis of pneumonia. All eligible patients were identified and a random sample was abstracted. We determined whether the use of guideline-concordant antibiotics was associated with 30-day mortality in an analysis that adjusted for potential confounders using propensity scores. Information was obtained on 420 patients with pneumonia. The mean (± SD) age was 63 ± 16 years, 355 were men, and 82 patients were initially admitted to the intensive care unit. At 30 days after presentation, 41 patients (9.8%) had died: 21 of 97 (21.7%) in the non-guideline-concordant group and 20 of 323 (6.2%) in the guideline-concordant group. Antibiotics were concordant with national guidelines in 323 patients. In the regression analysis, after adjustment for the propensity score, failure to comply with antimicrobial therapy guidelines was associated with increased 30-day mortality (odds ratio = 5.7; 95% confidence interval: 2.0 to 16.0). Receipt of antimicrobial regimens concordant with national published guidelines may reduce 30-day mortality among patients hospitalized with pneumonia. Am J Med. 2004;117:726 -731.