To Örebro University

BACKGROUND/OBJECTIVES: Studies show equal or better resolution of type 2 diabetes mellitus (T2D) and other metabolic outcomes after Roux-en-Y gastric bypass (RYGB) compared to sleeve gastrectomy (SG), but it is unclear whether this is related only to the higher weight loss after RYGB, or if there are weight-loss-independent factors. The objective of this study was to examine weight-loss-independent differences in metabolic outcomes between RYGB and SG.

METHODS: This study utilized the Scandinavian Obesity Surgery Registry and the Swedish National Diabetes Register. All included patients had presurgical T2D and matching was between RYGB or SG using a 1:1 propensity score, matching with a generalized linear model including age, sex, BMI at baseline, comorbidities (cardiovascular, dyslipidemia, sleep apnea, and hypertension), T2D parameters at baseline (HbA1c, number of T2D medications, insulin use, duration of T2D), year of surgery and percentage Total Weight Loss (%TWL) at nadir. The ensuing cohort was compared regarding remission and improvements in T2D, and other cardiometabolic outcomes, including major adverse cardiovascular events (MACE).

RESULTS: 1440 individuals (720 RYGB; 720 SG) were matched 1:1 using Propensity score. There were 494 (68.6%) patients in complete T2D remission at 2 years after RYGB, and 438 (60.8%) after SG, (OR: 0.75, 95% CI 0.60 - 0.93, p = 0.010) despite similar TWL (Standardized mean difference 0.12). SG also had a lower rate of pharmacological remission for T2D (OR 0.71, 95% CI 0.56-0.88, p = 0.002), and hypertension remission (OR 0.70, 95% CI 0.52-0.94, p = 0.019), but there was no significant difference in pharmacological remission regarding dyslipidemia (OR 0.83, 95%CI 0.66-01.04, p = 0.11). No difference was seen in the risk for MACE (SG vs. RYGB HR:1.45, 95%CI 0.89-2.38, p = 0.136).

CONCLUSIONS: RYGB is associated with a greater rate of T2D remission compared to SG. This study suggests that these improved outcomes are independent of the degree of weight loss.