Guideline Adherence of Perioperative Antibiotics and Surgical Site Infections in Noncardiac Surgery.

Importance: Despite nearly universal adherence to the Surgical Care Improvement Project (SCIP), surgical site infections (SSIs) persist. Compared with SCIP, which largely focuses on antibiotic timing, the Infectious Diseases Society of America (IDSA) guidelines provide a more comprehensive framework of antibiotic metrics, including procedure-specific antibiotic selection, weight-adjusted dosing, timing of the first dose, and appropriate redosing. Objective: To assess whether nonadherence to each antibiotic administration metric of IDSA guidelines is associated with SSIs. Design, Setting, and Participants: In this nationwide, multicenter, cross-sectional study, patients aged 18 years or older who underwent noncardiac surgeries involving a skin incision between January 1, 2014, and August 31, 2022, were included from merged data of the Multicenter Perioperative Outcomes Group, National Surgical Quality Improvement Program, and Michigan Surgical Quality Collaborative registries. Analyses were conducted between July 2, 2024, and April 24, 2025. Exposure: Nonadherence to IDSA-defined antibiotic metrics. Main Outcomes and Measures: The primary end point was SSI, defined as any superficial, deep tissue, or organ-space infection as recorded in the National Surgical Quality Improvement Program and Michigan Surgical Quality Collaborative registries. The association of nonadherence to IDSA guidelines (both overall and individually) was examined using hierarchical generalized linear mixed models. Results: Of 134 413 eligible surgical cases, a total of 119 236 patients (mean [SD] age, 56.2 [15.9] years; 58.1% women) from 37 institutions met the inclusion criteria, among whom 6796 (5.7%) had incomplete covariate data. Failure to adhere to any IDSA metric was common in 26.1% of cases, with individual nonadherence rates as follows: 13.3% for antibiotic choice, 9.0% for weight-adjusted dosing, 3.0% for timing relative to incision, and 4.8% for correct intraoperative redosing interval. Overall, SSIs occurred in 4.4% of cases. After adjusted analysis, guideline-nonadherent antibiotic administration was significantly associated with SSIs (relative risk [RR], 1.34 [95% CI, 1.26-1.43]). Nonadherence to antibiotic choice (RR, 1.43 [95% CI, 1.33-1.53]) and failure to appropriately redose intraoperatively (RR, 1.12 [95% CI, 1.02-1.24]) were significantly associated with SSIs. Conclusions and Relevance: This cross-sectional study found that IDSA guideline nonadherence, including incorrect antibiotic choice and missed intraoperative redosing, was common and associated with increased SSI risk, despite high adherence to SCIP timing metrics. Improving adherence to IDSA-recommended antibiotic selection and redosing may meaningfully reduce SSIs.