Inappropriate antibiotic therapy in Gram-negative sepsis increases hospital length of stay

Objectives: To describe the impact of initially inappropriate antibiotic therapy on hospital length of stay in Gram-negative severe sepsis and septic shock. Design: Retrospective cohort. Setting: Academic urban hospital. Patients: Patients with Gram-negative bacteremia (primary or secondary, nosocomial or non-nosocomial) and severe sepsis or septic shock. Interventions: None. Measurements and Main Results: We defined initially inappropriate antibiotic therapy as occurring when the patient either was not administered an antibiotic within 24 hrs of sepsis onset or was treated with an antibiotic to which the culprit pathogen was resistant in vitro. The cohort included 760 subjects (mean age 59.3 +/- 16.3 yrs, mean Acute Physiology and Chronic Health Evaluation II score 23.7 +/- 6.7). More than half of infections were nosocomial (55.1%), and Escherichia coli represented the most common pathogen (n = 225). Pseudomonas species were isolated in 17.4% of patients. Nearly one-third of patients (31.3%) received initially inappropriate antibiotic therapy. Patients administered initially inappropriate antibiotic therapy were more likely to have a nosocomial infection, to have underlying cancer or diabetes or both, to require chronic hemodialysis, and to undergo mechanical ventilation. Those administered initially inappropriate antibiotic therapy also faced higher inhospital mortality. The unadjusted median length of stay after sepsis onset in those administered initially inappropriate antibiotic therapy was 11 days compared to 9 days in those treated appropriately (p = .028 by log-rank test). In a Cox model controlling for the multiple confounders noted, initially inappropriate antibiotic therapy independently correlated with continued hospitalization (adjusted hazard ratio 1.19, 95% confidence interval 1.01-1.40, p = .044). Adjusting for these covariates indicated that initially inappropriate antibiotic therapy independently increased the median attributable length of stay by 2 days. Conclusions: Initially inappropriate antibiotic therapy occurs in one-third of persons with severe sepsis and septic shock attributable to Gram-negative organisms. Beyond its impact on mortality, initially inappropriate antibiotic therapy is significantly associated with length of stay in this population. Efforts to decrease rates of initially inappropriate antibiotic therapy may serve to improve hospital resource use by leading to shorter overall hospital stays. (Crit Care Med 2011; 39:46-51)