Impact of Hair Removal on Surgical Site Infection Rates: A Prospective Randomized Noninferiority Trial

Background Despite substantial prevention efforts, surgical site infections (SSIs) remain the most common health care-associated infection. It is unclear whether the Centers for Disease Control and Prevention recommendation to leave hair intact preoperatively reduces SSIs. Study Design A single-center, prospective, randomized, clinical trial was conducted from October 2009 to February 2015 in a 325-bed multispecialty, tertiary care teaching hospital to test the noninferiority of clipping hair to no hair removal in the prevention of SSIs. A total of 4,908 adults scheduled for elective general surgical procedures were screened for study participation. Of these, 600 were approached but refused, and 2,630 were excluded. Patients were randomized 1:1 to either the clipped group (n = 834) or the not-clipped group (n = 844). The clipped group had hair at the surgical site removed using disposable electric clippers. Of the randomized patients, 1,543 (768 in the clipped group and 775 in the not-clipped group) completed follow-up. The primary endpoint was the proportion of patients who could be evaluated and who had no SSI, as defined by CDC criteria. Results Baseline demographic, clinical, and surgical characteristics were similar between groups. The overall rate of SSI in the per-protocol analysis was 6.12% (47 of 768) in the clipped group and 6.32% (49 of 775) in the not-clipped group (absolute risk difference −0.20%; 95% CI −2.61% to 2.21%), p = 0.037). Because the absolute risk difference confidence interval included the prespecified noninferiority margin of 2%, we were unable to definitively demonstrate noninferiority for clipping hair. Conclusions Surgical site infection rates were similar whether hair was clipped or not in patients undergoing general surgical procedures.