Randomized Controlled Trial of Two Alcohol-based Preparations for Surgical Site Antisepsis in Colorectal Surgery

Objective: To compare 2 alcohol-based, dual-action skin preparations for surgical site infection (SSI) prevention in elective colorectal surgery. Background: Colorectal surgery is associated with the highest SSI rate among elective surgical procedures. Although evidence indicates that alcohol-based skin preparations are superior in SSI prevention, it is not clear if different alcohol-based preparations are equivalent in clean-contaminated colorectal procedures. Methods: We performed a blinded, randomized, noninferiority trial comparing iodine povacrylex-alcohol (IPA) and chlorhexidine-alcohol for elective, clean-contaminated colorectal surgery. The primary outcome was the presence or absence of SSI, defined as superficial or deep SSI, within 30 days postdischarge. A 6.6% noninferiority margin was chosen. Results: Between January 2011 and January 2015, 802 patients were randomized with 788 patients included in the intent to treat analysis (396 IPA and 392 chlorhexidine-alcohol). The difference in overall SSI rate between IPA (18.7%) and chlorhexidine-alcohol (15.9%) was 2.8% (P = 0.30). The upper bound of the 2.5% confidence interval of this difference was 8.9%, which is greater than the prespecified noninferiority margin of 6.6%. Other endpoints, including individual SSI types, time to SSI diagnosis, and length of stay were not different between the 2 arms. Conclusions: In patients undergoing elective, clean contaminated colorectal surgery, the use of IPA failed to meet criterion for noninferiority for overall SSI prevention compared with chlorhexidine-alcohol. Photodocumentation of wounds and rigorous tracking of outcomes up to 30 days postdischarge contributed to high fidelity to current standard SSI descriptions and wound classifications.