Effects of obesity surgery on type 2 diabetes mellitus Asian patients

Obesity is a major risk factor for the development of type 2 diabetes mellitus (T2DM). Surgery is the most effective treatment for morbid obesity, and it has been shown to lead to dramatic improvement in type T2DM. However, data concerning obese Asian patients have not been reported, and the mechanism of improving T2DM after bariatric surgery in this population remains speculative.

From April 1997 to March 2006, 1,375 patients undergoing obesity surgery were recruited for our study of the effects of weight loss surgery on type 2 diabetes mellitus (T2DM). Laparoscopic vertical banded gastric partition (LVBG) was performed in 552 patients (40.1%), laparoscopic gastric bypass in 660 patients (48.0%), and laparoscopic adjustable gastric banding (LAGB) in 140 patients (10.2%). Another 23 patients (1.7%) received open or revision surgery. We evaluated the clinical data and effect of obesity surgery on T2DM, impaired fasting glucose (IFG) and compared the changes with those with normal fasting glucose.

Among all the patients, 166 (12.1%) had impaired fasting glucose (IFG) and 247 (18.0%) had T2DM. Patients with IFG or DM were significantly older, more central obese, and they had higher insulin resistance and a higher HbA1C level than those with normal fasting glucose. The mean total weight loss for the population was 28.6%, 29.1%, 28.5%, 23.8%, and 24.4% (at 1, 2, 3, 5, and 7 years after surgery). There was no increase of surgical risk in T2DM or IFG patients. One year after operation, fasting plasma glucose returned to normal in 78.5% of T2DM patients and 94.7% of IFG patients. The HbA1C level returned to under 7.0 in 81.5% of T2DM and in 100% of IFG patients. Laparoscopic gastric bypass patients had a greater weight loss and a higher rate of glucose normalization (93.1%) than the LVBG patients (85.3%) and LAGB patients (73.9%), but no difference in HbA1C normalization.

Obesity surgery resulted in significant and sustained weight loss with a cure rate of T2DM up to 80% in morbidly obese Asian patients. Gastric bypass surgery had a better result in T2DM cure rate than LVBG and LAGB because of better weight reduction.