RT Journal Article SR Electronic T1 Complex And Simple Appendicitis: REstrictive or Liberal postoperative Antibiotic eXposure (CASA RELAX) using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): study protocol for a randomized controlled trial JF Trauma Surgery & Acute Care Open JO Trauma Surg Acute Care Open FD BMJ Publishing Group Ltd SP e000931 DO 10.1136/tsaco-2022-000931 VO 7 IS 1 A1 Daniel Dante Yeh A1 Gabrielle E Hatton A1 Claudia Pedroza A1 Gerd Pust A1 Alejandro Mantero A1 Nicholas Namias A1 Lillian S Kao YR 2022 UL http://tsaco.bmj.com/content/7/1/e000931.abstract AB Objectives After appendectomy for simple or complicated appendicitis, the optimal duration of postoperative antibiotics (postop abx) is unclear and great practice variability exists. We propose to compare restrictive versus liberal postop abx using a hierarchical composite endpoint which includes patient-centered outcomes and accounts for duration of antibiotic exposure.Methods/Design Participants with simple or complicated appendicitis undergoing appendectomy are randomly assigned to either restricted or liberal strategy. Eligible subjects declining randomization will be recruited to enroll in an observation only cohort. The primary endpoint is an ordinal scale of mutually exclusive clinical outcomes with within-category rankings determined by duration of antibiotic exposure. Subjects in both randomized and observation only cohorts will be analyzed as intention-to-treat, per-protocol, and as-treated. Exploratory Bayesian analyses will be performed.Conclusion The complex and simple appendicitis: restrictive or liberal postoperative antibiotic exposure multicenter randomized controlled trial will enroll surgical appendectomy patients and seeks to analyze if a strategy of restricted (compared with liberal) postoperative antibiotics results in similar clinical outcomes with the benefit of reduced antibiotic exposure.Trial registration number NCT05002829.No data are available. Not applicable, as this article describes only the study protocol. Data collection is currently ongoing.