Efficacy of aqueous olanexidine compared with alcohol-based chlorhexidine for surgical skin antisepsis regarding the incidence of surgical-site infections in clean-contaminated surgery: a randomized superiority trial

Background: Surgical-site antisepsis is used to prevent surgical-site infections (SSIs). Although several guidelines have indicated the efficacy of antiseptics, such as chlorhexidine, povidone-iodine, and olanexidine, in reducing the SSI rate, an optimal recommendation is still not established. The aim of this study was to evaluate the efficacy of aqueous olanexidine compared with chlorhexidine-alcohol as the optimal antiseptic for preventing SSI in clean-contaminated surgery. Methods: This multicentre randomized trial for surgical skin antisepsis in clean-contaminated gastrointestinal and hepatobiliary-pancreatic surgeries in five hospitals evaluated the efficacy of olanexidine and chlorhexidine-alcohol. The primary endpoint was 30-day SSI. Secondary outcomes included the occurrence of SSI types, intervention-related toxicity, and reoperation caused by SSI. Results: Overall, 700 patients from five institutions underwent randomization; 347 received olanexidine and 345 received chlorhexidine-alcohol in the full analysis set. The 30-day SSI rate was 12.4% (43 of 347) in the olanexidine group and 13.6% (47 of 345) in the chlorhexidine-alcohol group (adjusted risk ratio (aRR) 0.911 (95% c.i. 0.625 to 1.327); P = 0.626). No significant differences were observed between the groups regarding the secondary outcomes, including the occurrence of superficial incisional SSI, deep incisional SSI, organ/space SSI, and reoperation caused by SSI. Overall adverse effects were seen in two patients (0.58%) in the olanexidine group and in three patients (0.87%) in the chlorhexidine-alcohol group (aRR 0.663 (95% c.i. 0.111 to 3.951)). Conclusion: Olanexidine did not significantly reduce the occurrence of overall SSI compared with chlorhexidine-alcohol. Nevertheless, these findings provide valuable insights for developing novel surgical SSI management protocols. Registration number: UMIN 000049712 (University Hospital Medical Information Network Clinical Trials Registry).