S. D. Squires1, R. M. Cisco2, D. T. Lin2, A. W. Trickey3, E. Kebebew2, S. Gomar4, Y. Yuan4, C. D. Seib2,3,5 1Brigham Young University, College Of Life Sciences, Provo, UT, USA 2Stanford University School of Medicine, Department Of Surgery, Palo Alto, UT, USA 3Stanford-Surgery Policy Improvement Research and Education Center (S-SPIRE), Department Of Surgery, Palo Alto, CA, USA 4Atropos Health, Palo Alto, CA, USA 5Palo Alto Veterans Affairs Health Care System, Division Of General Surgery, Palo Alto, CA, USA
Introduction: Prophylactic antibiotics (pABX) are commonly used prior to thyroid operations despite clean case classification and randomized trial data showing no effect of pABX on the incidence of postoperative surgical site infection (SSI). The discordance between pABX use and published evidence may be due to concerns that high-risk patient populations are not represented in prior studies. The objective of this study was to estimate the effect of antibiotic prophylaxis on the incidence of SSI among patients undergoing thyroidectomy at a high-volume, tertiary referral center, accounting for SSI risk factors. We also sought to identify adverse outcomes associated with pABX use.
Methods: We performed a cohort study of all adults undergoing thyroid operations at a tertiary referral center from 2010-2019. The primary outcome was 30-day SSI, which was determined based on International Classification of Diseases (ICD) diagnosis codes and/or antibiotic use and further classified based on whether procedural intervention with wound aspiration or operative washout was required. Secondary outcomes included adverse effects of pABX use, including clostridium difficile infection within 30-days of surgery and allergic reaction on the day of surgery. The estimated effect of pABX on SSI was determined using propensity score matching based on patient demographics and comorbidities likely to influence SSI risk.
Results: We identified 2,455 adult patients who underwent thyroid operations during the study period (mean age 53 years, 74% female, 53% white), of whom 1,398 (56.9%) received pABX. Patients who received pABX had a higher mean Charlson Comorbidity Index score than patients who did not (4 vs. 2.9) and were less likely to be female (72.3% vs. 76.8%). The unadjusted incidence of SSI was higher in patients who received pABX than those who did not (7.7% vs. 3.7%, p<.001). Few patients with SSI required aspiration or operative washout (0.57% who received pABX vs. 0.19% who did not). After propensity score matching, pABX use showed no association with overall 30-day SSI (odds ratio [OR] 1.44, 95%CI 0.90-2.31) or SSI requiring procedural intervention (OR 2.002, 95%CI 0.10-118). Three patients experienced an allergic reaction in the pABX group and no patients developed clostridium difficile infection.
Conclusions: In a large cohort of patients with a high prevalence of comorbidity, the use of pABX was not associated with the incidence of SSI following thyroid surgery. Although adverse outcomes of pABX use were rare, efforts should be made to deimplement low-value pABX use in thyroid surgery.