Benefits and Risks Associated With Antibiotic Prophylaxis for Thyroid Operations.

Introduction: Prophylactic antibiotics (pABX) are commonly used prior to thyroid operations despite clean case classification. The objective of this study was to assess the association of antibiotic prophylaxis with the incidence of surgical site infection (SSI) among patients undergoing thyroidectomy.

Methods: We performed a cohort study of all adults undergoing thyroid operations at a tertiary referral center from 2010 to 2019. The primary outcome was 30-d SSI, based on diagnosis codes and/or antibiotic use and further classified based on whether wound aspiration or operative washout were required. The association between pABX and SSI was determined using propensity score matching based on patient demographics and comorbidities likely to influence SSI risk.

Results: We identified 2411 patients who underwent thyroid operations, of whom 1358 (56.3%) received pABX. Patients who received pABX had a higher mean Charlson-Deyo Comorbidity Index score than patients who did not (3.6 versus 2.9). The unadjusted incidence of SSI was higher in patients who received pABX than those who did not (6.1% versus 3.4%, P < 0.001). Few patients with SSI required aspiration or operative washout (0.29% who received pABX versus 0.19% who did not). After propensity score matching, pABX use showed no association with overall 30-d SSI (odds ratio 1.38, 95% confidence interval 0.84-2.26) or SSI requiring procedural intervention (odds ratio 3.01, 95% confidence interval 0.24-158).

Conclusions: In a large cohort of patients with a high prevalence of comorbidity, use of pABX was not associated with a decreased incidence of SSI following thyroid surgery. Efforts should be made to deimplement low-value pABX use in thyroid surgery.