Associations between initial antimicrobial therapy and medical outcomes for hospitalized elderly patients with pneumonia

Arch Intern Med. 1999 Nov 22;159(21):2562-72. doi: 10.1001/archinte.159.21.2562.


Background: Although medical practice guidelines exist, there have been no large-scale studies assessing the relationship between initial antimicrobial therapy and medical outcomes for patients hospitalized with pneumonia.

Objective: To determine the associations between initial antimicrobial therapy and 30-day mortality for these patients.

Methods: Hospital records for 12945 Medicare inpatients (> or = 65 years of age) with pneumonia were reviewed. Associations between initial antimicrobial regimens and 30-day mortality were assessed with Cox proportional hazards models, adjusting for baseline differences in patient characteristics, illness severity, and processes of care. Comparisons were made with patients treated with a non-pseudomonal third-generation cephalosporin alone (the reference group).

Results: Initial treatment with a second-generation cephalosporin plus macrolide (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.52-0.96), a non-pseudomonal third-generation cephalosporin plus macrolide (HR, 0.74; 95% CI, 0.60-0.92), or a fluoroquinolone alone (HR, 0.64; 95% CI, 0.43-0.94) was independently associated with lower 30-day mortality. Adjusted mortality among patients initially treated with these 3 regimens became significantly lower than that in the reference group beginning 2, 3, and 7 days, respectively, after hospital admission. Use of a beta-lactam/beta-lactamase inhibitor plus macrolide (HR, 1.77; 95% CI, 1.28-2.46) and an aminoglycoside plus another agent (HR, 1.21; 95% CI, 1.02-1.43) were associated with an increased 30-day mortality.

Conclusions: In this study of primarily community-dwelling elderly patients hospitalized with pneumonia, 3 initial empiric antimicrobial regimens were independently associated with a lower 30-day mortality. The more widespread use of these antimicrobial regimens is likely to improve the medical outcomes for elderly patients with pneumonia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Anti-Bacterial Agents*
  • Anti-Infective Agents / therapeutic use*
  • Drug Administration Schedule
  • Drug Therapy, Combination / therapeutic use*
  • Female
  • Hospitalization
  • Humans
  • Male
  • Pneumonia, Bacterial / drug therapy*
  • Pneumonia, Bacterial / mortality*
  • Proportional Hazards Models
  • Severity of Illness Index
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Anti-Infective Agents