The Role of Preoperative Antibiotics in Surgical Site Infection (SSI) Rate after Class I/Clean Gynaecologic Surgery at an Academic Safety Net Hospital.

Objectives: Examine whether preoperative antibiotics in class I/clean abdominal gynaecologic surgery decrease the incidence of surgical site infections (SSI).

Methods: Retrospective cohort study at academic safety net hospital of patients undergoing class I laparoscopic or open gynaecologic surgery between November 2013 and September 2017. Performance improvement initiative to administer preoperative antibiotics to all surgical patients starting July 2016.

Results: In total, 510 patients were included: 283 in the antibiotic group and 227 in the no-antibiotic group.

Primary Outcome: incidence of SSI. Baseline characteristics were similar between groups once balanced by propensity score method. In unweighted analysis, incidence of SSI decreased from 9.3% (21/227) in the no-antibiotics group to 4.9% (14/283) in antibiotics group, but this was not statistically significant (odds ratio (OR) 0.51 CI 0.25-1.03, P = 0.0598). Following of inverse probability of treatment weighting adjustments in weighted analysis, incidence of SSI was found to be significantly lower in patients who received antibiotics compared to patients who did not receive antibiotics across entry types (4.6% vs. 9.8%, OR 0.45; CI 0.22-0.90, P = 0.023). Weighted analysis demonstrated in the exploratory laparotomy group patients who received antibiotics had a lower incidence of SSI compared to patients who did not receive antibiotics (5.1% vs. 18.7%, OR 0.23; CI 0.08-0.68, P = 0.008). In the laparoscopy group, there was no difference between groups (4.4% vs. 5.4%, OR 0.81; CI 0.3-2.16, P = 0.675).

Conclusions: There is limited literature on SSI prevention/preoperative antibiotic use in class I gynaecologic surgeries. This study demonstrates antibiotics in class I procedures decrease SSI rates, specifically in open procedures. There was a lack of demonstrated benefit in laparoscopy.