Clinical Outcomes of Single Versus Double Anaerobic Coverage for Intra-abdominal Infections

Background Double anaerobic coverage is often used for intra-abdominal infections postoperatively. The primary objective of this study was evaluating length of hospital stay, in-hospital postoperative complications, and readmission within 30 days of discharge due to postoperative complications in patients who received piperacillin/tazobactam versus piperacillin/tazobactam plus metronidazole for intra-abdominal infections. The secondary objective was comparing in-hospital mortality and hospital-associated Clostridioides difficile infection between the 2 groups. Methods This retrospective cohort study included adults, who received either single or double anaerobic coverage postoperatively for at least 48 hours between January 1, 2016, and June 30, 2019. Statistical analysis involved matching patients 1:1 between the 2 groups based on Charlson Comorbidity Index, American Society of Anesthesiologists physical status classification, and surgical wound classification. Descriptive statistics and logistic regression were used to analyze the outcomes. Results Of 163 patients, 134 were matched 1:1 into single and double anaerobic coverage groups. The baseline characteristics of each group were similar except for diagnosis. Double anaerobic coverage was more often used for gastrointestinal perforations (38.8% vs 16.4%, P = 0.004) and single anaerobic coverage for acute cholecystitis (37.3% vs 9%, P < 0.001). In a multivariate analysis, double anaerobic coverage was associated with longer length of hospital stay (P = 0.003) compared with single anaerobic coverage. In-hospital mortality (6%) and hospital-associated C. difficile (1.5%) infection were only observed in the double anaerobic coverage group. Conclusions Double anaerobic coverage is associated with longer length of hospital stay and in-hospital postoperative complications.