Double-dose vs single-dose perioperative prophylactic antibiotics and surgical site infection in patients weighing ≥80 kg undergoing gastrointestinal surgery: a propensity score-matched study.

OBJECTIVE

Weight-based dosing of perioperative antibiotic prophylaxis is debatable in patients with heavier body weight. We evaluated whether a double (2 g) vs single (1 g) dose would reduce surgical site infections (SSIs) after gastrointestinal surgery in patients weighing ≥80 kg.

DESIGN

Single-centre retrospective cohort study.

SETTING

Primary referral centre in Japan.

PATIENTS: Patients with body weight ≥80 kg who underwent gastrointestinal surgery under general anaesthesia at our institution from 1st January, 2019, to 31st May, 2025, and received one of the following perioperative prophylactic antibiotics: cefazolin, cefmetazole, or flomoxef.

METHODS

Patients were divided into the single- vs double-dose groups. SSI was defined according to the Centers for Disease Control and Prevention criteria and compared after 2:1 propensity score matching for relevant covariates.

RESULTS

After matching (single dose, N = 100; double dose, N = 50), the baseline characteristics were balanced. SSIs occurred in 15% and 2% of the single- and double-dose group patients, respectively. Double dosing was associated with fewer SSIs (odds ratio, 0.117; 95% confidence interval, 0.003-0.804; P = 0.022). The SSI reduction potential was consistent in both logistic regression and lower intestinal surgery analyses.

CONCLUSIONS

Double dosing may benefit patients weighing ≥80 kg. Given the single-centre retrospective design, larger studies are required to confirm the effectiveness.