Effectiveness of Antibiotic Prophylaxis in Non-emergency Cholecystectomy Using Data from a Population-Based Cohort Study.

BACKGROUND: There is a variation in the administration of antibiotics prophylaxis to reduce the perceived risk of SSI in patients undergoing non-emergency cholecystectomy. The aim of this study was to determine the effectiveness of antibiotic prophylaxis following non-emergency cholecystectomy to prevent 30-day superficial surgical site infections (SSIs) using non-selected, nationally collected, prospective data. METHODS: Data were extracted from the CholeS study, which examined and independently validated the outcomes on consecutive patients following non-emergency cholecystectomy across 166 hospitals in the UK and Ireland. Patients who received antibiotic prophylaxis were exact matched to those who did not on variables associated with antibiotic prophylaxis. The primary outcome of interest was superficial SSI, and secondary outcomes included deep SSI, readmissions, complications and re-interventions within 30 days. RESULTS: Out of a total of 7327 patients included in the study, 4468 (61%) received antibiotic prophylaxis. These were matched to patients who did not receive antibiotic prophylaxis on a range of demographic and surgical factors, leaving 1269 pairs of patients for analysis. Within this cohort, patients receiving antibiotic prophylaxis had significantly lower rates of superficial SSI (0.7% vs. 2.3%, p = 0.001) and all-cause complications (5.8 vs. 8.0%, p = 0.031), but similar rates of deep SSI (1.0 vs. 1.4%, p = 0.473), readmissions (5.2 vs. 6.2%, p = 0.302) and re-interventions (2.6 vs. 3.7%, p = 0.093). The number needed to treat to prevent one superficial SSI was 45 (95% confidence interval 24-662). CONCLUSIONS: Antibiotics appear effective at reducing SSI after non-emergency cholecystectomy. However, due to the high number needed to treat it is unclear whether they provide a worthwhile clinical benefit to patients.