Impact of Preoperative Glucagon-Like Peptide-1 Receptor Agonist Use on Short-Term and Long-Term Outcomes Following Thoracic and/or Lumbar Fusion for Spinal Deformity: A BMI-Stratified Cohort Study

Study design: A retrospective cohort study. Objective: To evaluate the association between preoperative use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and postoperative outcomes following thoracic and/or lumbar fusion for spinal deformity, stratified by body mass index (BMI). Summary of background data: Thoracic and lumbar fusion surgeries are increasingly performed to treat spinal deformities, particularly among older and obese populations. GLP-1 RAs, originally developed for diabetes management, are now commonly prescribed for weight loss across a wide BMI range. Although these agents have shown systemic metabolic and anti-inflammatory benefits, their effects on spine surgery outcomes remain poorly characterized. Methods: A retrospective analysis of a national claims database (2010–2023) was conducted. Patients undergoing thoracic and/or lumbar fusion for spinal deformity were identified and stratified into six BMI categories. GLP-1 RA users were identified through preoperative pharmacy claims and matched 1:4 to nonusers based on age, sex, and Charlson Comorbidity Index. Primary endpoints included 90-day medical complications and 2-year and 10-year surgical outcomes. Cox proportional hazards models were used to assess long-term risks, with Bonferroni correction applied for multiple comparisons. Results: Of 214,922 patients, 14,047 GLP-1 RA users were matched to 56,056 controls. GLP-1 RA use was associated with significantly lower rates of 90-day complications—including infections, pneumonia, venous thromboembolism, and sepsis—in patients with BMI ≥25. No significant differences were observed in 2-year or 10-year rates of revision for infection, pseudoarthrosis, or mechanical failure. However, GLP-1 RA users exhibited a consistently increased risk of decompressive laminectomy at both 2 and 10 years across all BMI categories. Conclusion: Preoperative use of GLP-1 RAs is associated with improved short-term postoperative outcomes following thoracic and/or lumbar fusion, particularly in overweight and obese patients. The observed increase in long-term rates of decompressive laminectomy warrants further investigation to elucidate potential skeletal effects and underlying mechanisms. Level of Evidence: Level III.