The Effect of Body Mass Index on the Efficacy of Semaglutide Use at the Time of Total Knee Arthroplasty.

BACKGROUND: This study evaluated the impact of semaglutide on postoperative complications following total knee arthroplasty by body mass index (BMI) class. METHODS: A retrospective analysis of a national claims database was performed for patients undergoing primary total knee arthroplasty for osteoarthritis who had an active semaglutide prescription from January 2010 to April 2023. Patients were divided into nonobese (BMI < 30), obese (BMI 30.0 to 39.9), and morbidly obese (BMI ≥ 40) groups. Semaglutide users were propensity score matched to nonusers, yielding nonobese (7,402 versus 36,884), obese (4,034 versus 20,134), and morbidly obese (2,383 versus 11,853). Outcomes included 90-day medical complications, 90-day readmissions, and 90-day and 2-year implant-related complications. Univariate and multivariate regressions compared outcomes within BMI groups. RESULTS: In the nonobese group, semaglutide users had significantly lower odds of deep vein thrombosis (odds ratio (OR) 0.68; 95% confidence interval (CI) 0.57 to 0.81; P < 0.001), pulmonary embolism (OR 0.49; 95% CI 0.34 to 0.70; P < 0.001), and pneumonia (OR 0.69; 95% CI 0.53 to 0.89; P = 0.004). In obese patients, semaglutide users had significantly lower odds of 90-day periprosthetic joint infection (OR 0.53; 95% CI 0.38 to 0.76; P < 0.001), 2-year periprosthetic joint infection (OR 0.65; 95% CI 0.52 to 0.81; P < 0.001), 90-day revisions (OR 0.54; 95% CI 0.35 to 0.85; P = 0.008), deep vein thrombosis (OR 0.67; 95% CI 0.54 to 0.82; P < 0.001), pulmonary embolism (OR 0.39; 95% CI 0.23 to 0.62; P < 0.001), and pneumonia (OR 0.69; 95% CI 0.49 to 0.90; P = 0.008). In morbidly obese patients, semaglutide use was associated with significantly lower rates of 90-day aseptic loosening and myocardial infarction (both P < 0.001). CONCLUSIONS: Our findings support a BMI-based approach to perioperative semaglutide use, particularly in patients who have a BMI >30. LEVEL OF EVIDENCE: III, retrospective cohort.