Impact of Antimicrobial Stewardship on Outcomes in Hospitalized Veterans With Pneumonia

Purpose: The purpose of this study was to evaluate the impact of an antimicrobial stewardship program (ASP) on outcomes for inpatients with pneumonia, including length of stay, treatment duration, and 30-day readmission rates.

Methods: A retrospective chart review comparing outcomes of veterans admitted with pneumonia before (2005-2006) and after (2013-2014) implementation of an ASP was conducted; pneumonia was defined according to International Classification of Diseases, Ninth Revision (ICD-9) codes. Infectious diseases physicians and pharmacist in the ASP provided appropriate recommendations to the primary medicine teams. Bivariate analysis of baseline characteristics and comorbid conditions were performed between the time frames. Least squares regression was used to analyze length of stay, time of IV to PO conversions, and duration of antibiotics. Multivariate logistic regressions were used to determine odds of 30-day readmission and odds of Clostridium difficile infections between time periods.

Findings: There were 86 patients in the pre-ASP period and 88 patients in the ASP period. Mean length of stay decreased from 8.1 to 6.6 days (P = 0.02), total duration of antibiotic therapy decreased from 12 to 8.5 days (P < 0.0001), and time of IV to PO antibiotic conversions decreased from 5.3 to 3.9 days (P = 0.0003), before ASP and during ASP, respectively. The odds ratio of 30-day readmission before ASP was 2.78 and 0.36 during the ASP (P = 0.05). The odds ratios of Clostridium difficile infections before ASP was 2.08 and 0.48 during the ASP (P = 0.37).

Implications: The ASP interventions were associated with shorter durations of therapy, shorter lengths of stay, and lower rates of readmission and Clostridium difficile infections within 30 days. Limitations of this study are retrospective cohort design, small study population, limited study population diversity, and non-concurrent cohort times periods.