Outcomes of Restricted versus Liberal Post-Operative Antibiotic Use in Patients Undergoing Appendectomy: A DOOR/RADAR Post Hoc Analysis of the EAST Appendicitis MUSTANG Study

Background: There is no consensus on the duration of antibiotic use after appendectomy. We hypothesized that restricted antibiotic use is associated with better clinical outcomes. Patients and Methods: We performed a post hoc analysis of the Eastern Association for the Surgery of Trauma (EAST) Multicenter Study of the Treatment of Appendicitis in America–Acute, Perforated, and Gangrenous (MUSTANG) study using the desirability of outcome ranking/response adjusted for duration of antibiotic risk (DOOR/RADAR) framework. Three separate datasets were analyzed based on restricted versus liberal post-operative antibiotic groups: simple appendicitis (no vs. yes); complicated appendicitis, only four days (≤24 hours vs. 4 days); and complicated appendicitis, four or more days (≤24 hours vs. ≥4 days). Patients were assigned to one of seven mutually exclusive DOOR categories RADAR ranked within each category. DOOR/RADAR score pairwise comparisons were performed between all patients. Each patient was assigned either 1, 0, or −1 if they had better, same, or worse outcomes than the other patient in the pair, respectively. The sum of these numbers (cumulative comparison score) was calculated for each patient and the group medians of individual sums were compared by Wilcoxon rank sum. Results: For simple appendicitis, the restricted group had higher median sums than the liberal group (552 [552,552] vs. −1,353 [−1,353, −1,353], p < 0.001). For both complicated appendicitis analyses, the restricted group had higher median sums than the liberal: only 4 (196 [23,196] vs. −121 [−121, −121], p < 0.02) and 4 or more (660 [484,660] vs −169 [−444,181], p < 0.001). Conclusions: Restricted post-operative antibiotic use in patients after appendectomy is a dominant strategy when considering treatment effectiveness and antibiotic exposure.