Effect of Roux-en-Y Gastric Bypass for Patients with Type 2 Diabetes Mellitus and a BMI < 32.5 kg/m2: a 6-Year Study in Chinese Patients

Background Roux-en-Y gastric bypass (RYGB) is an effective treatment for morbidly obese patients to improve type 2 diabetes mellitus (T2DM). Recently, T2DM patients with a lower body mass index (BMI) have been receiving more attention, and these patients could benefit from RYGB. Methods Fifty-two patients with T2DM underwent RYGB between October 2008 and December 2012 in our hospital. Weight, BMI, oral glucose tolerance test (OGTT), insulin release test (IRT), C-peptide release test (CRT), glycosylated hemoglobin (HbA1c), and lipid metabolic parameters were measured at baseline and at 3 and 6 months and 1, 2, 3, 4, 5, and 6 years after surgery. Results The mean age of the 52 patients was 46.8 +/- 9.5 years, and 57.7% were male. The mean duration of T2DM was 6.5 +/- 4.6 years. Compared with the baseline values, weight and BMI were significantly decreased at several time points after surgery. HbA1c decreased from 8.2 +/- 1.7% at baseline to 6.5 +/- 1.4% at 3 months, 6.5 +/- 1.4% at 6 months, 7.2 +/- 1.3% at 4 years, and 7.5 +/- 1.2% at 6 years. OGTT, OGTT-IRT, and OGTT-CRT improved after surgery. There was a decrease in triglycerides (TGs), total cholesterol (TC), and low-density lipoprotein (LDL) and an increase in high-density lipoprotein (HDL). At 6 years after surgery, 16.7% of patients achieved complete remission of T2DM, and 66.7% achieved improvement in T2DM. Conclusion RYGB may be a safe and effective treatment for T2DM patients with a BMI < 32.5 kg/m(2)in China. However, a long-term study without loss to follow-up is necessary for better evaluation.