Differences in clinical and cost-effectiveness between cefmetazole and flomoxef for the prevention of surgical site infection in elective colorectal surgery: A single-center, retrospective cohort study

Surgical site infection (SSI) is associated with increased morbidity and mortality rates, postoperative length of stay (pLOS), and medical costs. In colorectal surgery, cefmetazole (CMZ) and flomoxef (FMOX) are predominantly used in Japan, and they have almost the same spectrum of antibiotic activity against SSI pathogens, and an approximately four-fold cost difference (CMZ: ∼4$, FMOX: ∼16$). However, the difference between these antibiotics in SSI prophylaxis in colorectal surgery remains poorly understood. We performed a single-center retrospective cohort study to investigate the prophylactic effects of these antibiotics, pLOS, and hospitalization costs. Patients who underwent elective colorectal surgery between April 2016 and March 2020 were considered for this study. Of the 634 patients, 316 (49.8%) were eligible. The SSI rates in the CMZ and FMOX groups were 14.7% and 12.5%, respectively. The incidence of organ/space SSI was approximately two-fold lower in the CMZ group than in the FMOX group (4.4% vs. 9.4%). Multivariable regression analysis revealed that CMZ was not significantly related to SSI, with an adjusted odds ratio of 1.21 (95% confidence interval [CI]: 0.52–2.82) and did not induce a significant difference in pLOS (difference ratio: 0.951 [95% CI: 0.868–1.041]). Hospitalization costs were reduced in the CMZ group (difference ratio, 0.951 [95% CI: 0.907–0.998], p = 0.042). The sensitivity analysis also showed results similar to the above findings. Our study showed that CMZ could be a cost-effective antibiotic with similar efficacy for SSI prophylaxis in colorectal surgery, compared with FMOX.