Effectiveness of Shorter Versus Longer Durations of Therapy for Common Inpatient Infections Associated with Bacteremia: A Multicenter, Propensity-Weighted Cohort Study.

BACKGROUND: National guidelines for pneumonia (PNA), urinary tract infection (UTI), and acute bacterial skin and skin structure infection (ABSSSI) do not address treatment duration for infections associated with bacteremia. We evaluated clinical outcomes of patients receiving shorter (5-9 days) versus longer (10-15 days) duration of antibiotics. METHODS: This was a multicenter retrospective cohort study of inpatients with uncomplicated PNA, UTI, or ABSSSI and associated bacteremia. The primary outcome was clinical failure, a composite of rehospitalization, re-initiation of antibiotics, or all-cause mortality within 30 days of antibiotic completion. Secondary outcomes included individual components of the primary outcome, Clostridioides difficile infection, and antibiotic-related adverse effects necessitating change in therapy. A propensity score-weighted logistic regression model was used to mitigate potential bias associated with non-random assignment of treatment duration. RESULTS: Of 408 patients included, 123 received a shorter treatment duration (median 8 days) and 285 received a longer duration (median 13 days). In the propensity-weighted analysis, the probability of the primary outcome was 13.5% in the shorter group and 11.1% in the longer group (average treatment effect, 2.4%; odds ratio [OR], 1.25; 95% confidence interval [CI], 0.65-2.40; p=0.505). However, shorter courses were associated with higher probability of restarting antibiotics (OR, 1.62; 95% CI, 1.01-2.61; p=0.046) and C. difficile infection (OR, 4.01; 95% CI, 2.21-7.59; p<0.0001). CONCLUSIONS: Shorter courses of antibiotic treatment for PNA, UTI, and ABSSSI with bacteremia were not associated with increased overall risk of clinical failure; however, prospective studies are needed to further evaluate the effectiveness of shorter treatment durations.