Guideline-concordant antibiotic use and survival among patients with community-acquired pneumonia admitted to the intensive care unit

Objective: This study evaluated the survival benefit of US community-acquired pneumonia (CAP) practice guidelines in the intensive care unit (ICU) setting. Methods: We conducted a retrospective cohort study of adult patients with CAP who were admitted to 5 community hospital ICUs between November 1, 1999, and April 30, 2000. The guidelines for antibiotic prescriptions were the 2007 Infectious Diseases Society of America/American Thoracic Society guidelines. Guideline-concordant antimicrobial therapy was defined as a β-lactam plus fluoroquinolone or macrolide, antipseudomonal β-lactam plus fluoroquinolone, or antipseudomonal β-lactam plus aminoglycoside plus fluoroquinolone or macrolide. Patients with a documented β-lactam allergy were considered to have received guideline-concordant therapy if they received a fluoroquinolone with or without clindamycin, or aztreonam plus fluoroquinolone with or without aminoglycoside. All other antibiotic regimens were considered to be guideline discordant. Time to clinical stability, time to oral antibiotics, length of hospital stay, and in-hospital mortality were evaluated with regression models that included the outcome as the dependent variable, guidelineconcordant antibiotic therapy as the independent variable, and the Pneumonia Severity Index (PSI) score and facility as covariates. Results: The median age of the 129 patients included in the study was 71 years (interquartile range, 60-79 years). Sixty-two of 129 patients (48%) were male. Comorbidities included liver dysfunction (7 patients [5%]), heart failure (62 [48%]), renal dysfunction (39 [30%]), cerebrovascular disease (21 [16%]), and cancer (14 [11%]). The median (25th-75th percentile) PSI score was 119 (98-142), and overall mortality was 19% (25 patients). Patient demographics were similar between groups. Fifty-three patients (41%) received guideline-endorsed therapies. Guideline-discordant therapy was associated with an increase in inpatient mortality (25% vs 11%; odds ratio = 2.99 [95% CI, 1.08-9.54]). Receipt of guideline-concordant antibiotics was not associated with reductions in time to clinical stability, time to oral antibiotics, or length of hospital stay when patients who died were excluded from the analysis. Conclusion: Guideline-concordant empiric antibiotic therapy was associated with improved survival among these patients with CAP who were admitted to 5 ICUs.