Validation of the individualized metabolic surgery score for bariatric procedure selection in the merged data of two randomized clinical trials (SLEEVEPASS and SM-BOSS)

Abstract

Background: LSG and LRYGB are globally the most common bariatric procedures. IMS score categorizes T2D severity (mild, moderate, and severe) based on 4 independent preoperative predictors of long-term remission as follows: T2D duration, number of diabetes medications, insulin use, and glycemic control. IMS score has not been validated in a randomized patient cohort.

Objectives: To assess the feasibility of individualized metabolic surgery (IMS) score in facilitating procedure selection between laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) for patients with severe obesity and type 2 diabetes (T2D).

Setting: Merged individual patient-level 5-year data of 2 large randomized clinical trials (SLEEVEPASS and SM-BOSS [Swiss Multicenter Bypass or Sleeve Study]).

Methods: IMS score was calculated for study patients and its performance was analyzed.

Results: One hundred thirty-nine out of 155 patients with T2D had available preoperative data to calculate IMS score as follows: mild stage (n = 41/139), moderate stage (n = 77/139), severe stage (n = 21/139). At 5 years, 135 (87.1%, 67 LSG/68 LRYGB) were available for follow-up and 121 patients had both pre- and postoperative data. Diabetes remission rates according to preoperative IMS score were as follows: mild stage 87.5% (n = 14/16) after LSG and 85.7% (n = 18/21) after LRYGB (P = .999), moderate stage 42.9% (n = 15/35) and 45.2% (n = 14/31) (P = .999), and severe stage 18.2% (n = 2/11) and 0% (n = 0/7) (P = .497), respectively. The T2D remission rate varied significantly between the stages as follows: mild versus moderate odds ratio (OR) 8.3 (95% CI, 2.8-24.0; P < .001), mild versus severe OR 52.2 (95% CI 9.0-302.3; P < .001), and moderate versus severe OR 6.3 (95% CI, 1.3-29.8; P = .020).

Conclusions: In our study, remission rates of T2D were not statistically different after LSG and LRYGB among all patients and among patients with mild, moderate, and severe diabetes stratified by the IMS score. However, the study may be underpowered to detect differences due to small number of patients in each subgroup. IMS score seemed to be useful in predicting long-term T2D remission after bariatric surgery.

Keywords: Bariatric surgery; IMS score; Roux-en-y gastric bypass; Sleeve gastrectomy; Type 2 diabetes.