Importance: Ninety percent of cases of acute calculous cholecystitis are of mild (grade I) or moderate (grade II) severity. Although the preoperative and intraoperative antibiotic management of acute calculous cholecystitis has been standardized, few data exist on the utility of postoperative antibiotic treatment.
Objective: To determine the effect of postoperative amoxicillin plus clavulanic acid on infection rates after cholecystectomy.
Design, setting, and patients: A total of 414 patients treated at 17 medical centers for grade I or II acute calculous cholecystitis and who received 2 g of amoxicillin plus clavulanic acid 3 times a day while in the hospital before and once at the time of surgery were randomized after surgery to an open-label, noninferiority, randomized clinical trial between May 2010 and August 2012.
Interventions: After surgery, no antibiotics or continue with the preoperative antibiotic regimen 3 times daily for 5 days.
Main outcomes and measures: The proportion of postoperative surgical site or distant infections recorded before or at the 4-week follow-up visit.
Results: An imputed intention-to-treat analysis of 414 patients showed that the postoperative infection rates were 17% (35 of 207) in the nontreatment group and 15% (31 of 207) in the antibiotic group (absolute difference, 1.93%; 95% CI, -8.98% to 5.12%). In the per-protocol analysis, which involved 338 patients, the corresponding rates were both 13% (absolute difference, 0.3%; 95% CI, -5.0% to 6.3%). Based on a noninferiority margin of 11%, the lack of postoperative antibiotic treatment was not associated with worse outcomes than antibiotic treatment. Bile cultures showed that 60.9% were pathogen free. Both groups had similar Clavien complication severity outcomes: 195 patients (94.2%) in the nontreatment group had a score of 0 to I and 2 patients (0.97%) had a score of III to V, and 182 patients (87.8%) in the antibiotic group had a score of 0 to I and 4 patients (1.93%) had a score of III to V.
Conclusions and relevance: Among patients with mild or moderate calculous cholecystitis who received preoperative and intraoperative antibiotics, lack of postoperative treatment with amoxicillin plus clavulanic acid did not result in a greater incidence of postoperative infections.
Trial registration: clinicaltrials.gov Identifier: NCT01015417.