Differential impact of pre-operative tirzepatide compared to glucagon-like-peptide-1 single receptor agonists on outcomes of spinal fusion surgery in obese patients

Study Design: Retrospective, propensity score-matched cohort study. Purpose: To determine if outcomes following spinal fusion differ between obese patients prescribed Tirzepatide and single receptor glucagon-like-peptide-1 (srGLP-1) agonists preoperatively. Methods: Data was collected from the TriNetX Research Network. Obese patients undergoing spinal fusion that were prescribed tirzepatide alone in the 6 months preceding surgery, were matched 1:1 based on demographics, comorbidities, medication use, and surgical procedure with those prescribed an srGLP-1 agonist alone in the year prior to surgery. Early (90-day) outcomes included UTI, thrombotic or embolic events, and AKI. Long-term outcomes (2 years) include revision, pseudarthrosis, and post-laminectomy syndrome. Results: A total of 918 matched pairs were analyzed. At 90-days after surgery, tirzepatide patients experienced fewer embolic or thrombotic events (RR 0.41, 95% CI 0.22–0.76, p = 0.003), lower UTI rates (RR 0.47, 95% CI 0.32–0.69, p < 0.001) and less AKIs (RR 0.42, 95% CI 0.26–0.69, p < 0.001) compared to srGLP-1 patients. At 2 years after surgery tirzepatide users had fewer instances of revision (RR 0.65, 95% CI 0.49–0.87, p = 0.003), pseudarthrosis (RR 0.41, 95% CI 0.25–0.68, p < 0.001), post-laminectomy syndrome (RR 0.58, 95% CI 0.31–0.68, p < 0.001) compared to srGLP-1 users. Conclusions: In a propensity-matched analysis, obese spinal fusion patients treated with Tirzepatide compared to srGLP-1 agonists, had lower rates of early postoperative thrombotic and embolic events, UTIS, and AKIs. Additionally, the Tirzepatide fusion cohort had significantly lower rates of pseudarthrosis, revision surgery, and post-laminectomy syndrome 2 years after surgery. These findings support the potential protective physiological impact of Tirzepatide over srGLP-1s in obese patients undergoing spinal fusion.