GLP-1 Agonist Use Leads to Earlier Return of Bowel Function Following Lumbar Fusion

Retrospective cohort. To compare surgical outcomes and patient-reported outcome measures (PROMs) after lumbar fusion between type 2 diabetes mellitus (T2DM) patients with versus without chronic preoperative glucagon-like-peptide-1 (GLP-1) receptor agonist use. T2DM is a risk factor for adverse outcomes after spine surgery. GLP-1 receptor agonists are increasingly prescribed for patients with T2DM. However, few studies have investigated their impact on lumbar fusion outcomes. T2DM patients undergoing primary, elective posterior lumbar fusion were included; GLP-1 agonist use was identified. Demographic/surgical data were collected by manual chart review. Primary outcomes included surgical outcomes, complications, wound healing, and return of postoperative bowel function. Return of bowel function was defined as flatulence or a bowel movement. Secondary outcomes included PROMs. A Poisson regression predicting the day of postoperative return of bowel function was performed. Fifty-seven patients had preoperative GLP-1 agonist use, whereas 60 did not. Patients taking GLP-1 agonists were more commonly female (54.4% vs. 30.5%, P =0.016) and had higher mean body mass index (BMI) (34.6±5.96 vs. 32.6±6.08). Otherwise, the groups were demographically/surgically similar. Patients taking GLP-1 agonists demonstrated quicker return of bowel function (1.35±1.30 vs. 1.90±0.77 d, P =0.013). There were no differences in discharge disposition, length of stay, inpatient complications, postoperative wound abnormalities, or PROMs. Regression showed that GLP-1 agonist use independently decreased the time to return of bowel function (rate ratio: 0.69, P =0.028). This study suggests that chronic GLP-1 agonist use does not lead to inferior short-term outcomes or long-term PROMs after lumbar fusion. GLP-1 agonists may benefit the return of bowel function, potentially due to chronic gut motility adaptations and/or anti-inflammatory properties. Further study is required to support these findings.