Obesity often plays a key role in the development and progression of type 2 diabetes mellitus (T2DM), and metabolic surgery is a powerful tool for treating T2DM and inducing T2DM remission.(1,2) Those with severe obesity generally present with greater insulin resistance and worse metabolic complications in comparison to those with lower weight.1 Higher BMI is included as a predictor of diabetes remission following metabolic surgery in the ABCD score, a grading system which has been validated in a number of external cohorts.(3-5) However, there is a relative lack of data regarding the impact of having a baseline BMI (bBMI) ≥ 50 kg/m2 on the likelihood of T2DM remission following metabolic surgery. Thus, this cohort study aimed to examine whether rates of T2DM remission differ between adults with bBMI ≥ 50 kg/m2 versus bBMI < 50 kg/m2 following a comprehensive metabolic program including surgery.

This retrospective cohort study examined prospectively collected data from adults with pre-existing T2DM that were enrolled in a metabolic program at an Australian tertiary hospital and underwent metabolic surgery between 01/06/2018 and 31/05/2024. The primary outcome was complete T2DM remission (defined as HbA1c < 6.0 % and at least 3 months off glucose-lowering medications with consideration of Australian Diabetes Society6 criteria) at 12 months after metabolic surgery.

Percent weight loss [mean(SD)] at 12 months after metabolic surgery was significantly higher amongst those with bBMI ≥ 50 kg/m2 (N = 44) in comparison to those with bBMI < 50 kg/m2 (N = 44) [-29.9(11.4) vs -24.5(10.2), p = 0.037]. A markedly higher proportion of patients with bBMI ≥ 50 kg/m2 attained T2DM remission at 12 months after metabolic surgery when compared to those with bBMI < 50 kg/m2 (66.7% vs 37.8%, p = 0.021), and this remained significant after adjustment for percent weight loss and type of metabolic surgery (aOR 4.030, 95% CI 1.498 - 10.843); the difference between groups was no longer significant after adjustment for baseline HbA1c, baseline age, and duration of T2DM (aOR 2.869, 95% CI 0.911 - 9.037).

At 12 months after metabolic surgery, when compared to the group with bBMI < 50kg/m2, those with bBMI ≥ 50 kg/m2 attained a significantly higher percent weight loss and there was also a markedly higher proportion with T2DM remission, though the difference between groups for the latter outcome was no longer significant after adjustment for baseline factors.