Background

Increasing body mass index (BMI) is linearly associated with increasing components of metabolic syndrome (MS) and hence a strong surrogate for poor metabolic health. While the benefits of metabolic bariatric surgery (MBS) to restore metabolic health are well established, the utility of preoperative weight loss is unclear. The purpose of this study was to evaluate the effect of preoperative weight loss on the rate of postoperative metabolic restoration.

Methods

All patients who underwent primary vertical sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RNYGB) at a single academic institution, between 2015 and 2022 were retrospectively reviewed. Patients were stratified into groups based on 5% increments of preoperative excess weight loss (EWL). Primary endpoints included BMI and %EWL at 3, 6, 9 and 12 months postoperatively. Metabolic restoration was defined as BMI < 30 and %EWL 50. Outcomes were analyzed using multivariate (Logit) analyses.

Results

During the study period, 1280 patients underwent primary MBS (368=Sleeve, 912=RNYGB). For each 5% increase in EWL preoperatively, there was a statistically significant increase of achieving a BMI<30 at three (OR=1.72, 95%CI 1.44-2.05, p<0.001), six (OR=1.52, 95%CI 1.32-1.75, p<0.001), nine (OR=1.35, 95%CI 1.13-1.60, p=0.001), and twelve (OR=1.27, 95%CI 1.13-1.44, p<0.001) months postoperatively. Similar results were seen for 50%EWL at each time interval. Patients who underwent RNYGB were more likely to achieve metabolic restoration at each time interval as compared to SG.

Conclusions

In a dose-dependent manner, greater preoperative weight loss predicts more rapid metabolic restoration in the first year after MBS.