Mid-Long-Term Effect of Metabolic Surgery on Type 2 Diabetes in Nonobese Patients: a Meta-analysis.

BACKGROUND: This study aimed to perform a meta-analysis regarding the mid-long-term effect (≥ 2-year follow-up) of metabolic surgery on T2DM in non-obese patients. METHODS: PubMed, EMBASE and CENTRAL databases were searched for clinical studies from inception to March 2023. Stata 12.0 was used for data aggregation. Sensitivity, subgroup, and meta-regression analyses were performed when feasible. RESULTS: This meta-analysis included 18 articles involving 548 patients. A pooled rate of 47.5% of T2DM remission was found after metabolic surgery. To be more specific, 83.5% was obtained for hemoglobin A1c (HbA1c) < 7.0%, 45.1% for HbA1c < 6.5%, and 40.4% for HbA1c < 6.0%. Subgroup analysis showed that one-anastomosis gastric bypass (OAGB) had a higher remission rate (93.9%) than other surgeries. Studies conducted in America had a higher remission rate (61.4%) than in Asia (43.6%). Meta-regression analysis displayed that publication year, number of patients, study design, preoperative age, BMI, and quality assessment score were not significantly associated with T2DM remission rate. Additionally, metabolic surgery could result in significant reductions in BMI (-4.133 kg/m2), weight (-9.874 kg), HbA1c (-1.939%), fasting blood glucose, fasting C-peptide, and fasting insulin. However, metabolic surgery seemed to have poorer glycemic control in non-obese than obese T2DM patients. CONCLUSION: A moderate mid-long-term effect of T2DM remission was observed after metabolic surgery in non-obese patients. However, we still need more prospective multi-institutional studies using the same definitions for diabetes and the same surgical technique for the surgery. Without this, the exact role of bariatric surgery in non-obese patients is unanswered.