Supplementary Material for: Antibiotic Prophylaxis against Surgical Site Infection after Open Hernia Surgery: A Systematic Review and Meta-Analysis

Objective: The role of antibiotic prophylaxis (AP) in the prevention of surgical site infection (SSI) after hernia repair is debated. We conducted this systematic review and meta-analysis to assess the evidence on the value of prophylactic antibiotics in reducing the risks of SSI after open hernia surgery. Methods: We ran an online and manual search to identify relevant randomized controlled trials that compared prophylactic antibiotics to nonantibiotic controls in patients undergoing open surgical hernia repair. Data on SSI risk were extracted and pooled as risk ratios (RRs) with 95% confidence intervals (95% CIs), using RevMan software. We further used the Cochrane risk of bias tool and GRADE assessment to evaluate the quality of generated evidence. Results: Twenty-nine studies (N = 8,616 patients) were included in the current analysis. Antibiotic prophylaxis reduced the risk of SSI in open hernia repair patients (RR = 0.65, 95% CI = 0.53, 0.79). Subgroup analysis showed a significant benefit for antibiotics in mesh repair patients (RR = 0.60, 95% CI = 0.48, 0.76) yet no significant difference in SSI risk after herniorrhaphy (RR = 0.86, 95% CI = 0.54, 1.36). In addition, AP was associated with a significant reduction in superficial SSI risk (RR = 0.56, 95% CI = 0.43, 0.72) but not deep SSI (RR = 0.70, 95% CI = 0.30, 1.62). Further analysis showed a significant reduction in SSI risk with amoxicillin/clavulanic acid and cefazolin but not with cefuroxime. Conclusion: The present meta-analysis suggests that AP is beneficial prior to open mesh hernia repair. However, the quality of evidence was low, and further well-designed trials are needed.