Bariatric surgery reduces risk factors for development of type 2 diabetes mellitus in morbidly obese, nondiabetic patients.

BACKGROUND: Patients with morbid obesity have a high risk of developing type 2 diabetes mellitus (T2DM). Important risk factors include body mass index (BMI), waist circumference, and insulin resistance. In this prospective study, we investigated if preoperative lifestyle changes followed by bariatric surgery could reduce these risk factors.
METHODS: Forty nondiabetic obese patients aged 27-57 years participated. Baseline BMI was 36.1-65.6 kg/m(2). Fasting glucose, C-peptide, and glycated hemoglobin (HbA1c) were measured at baseline and 1 year after surgery. The patients underwent lifestyle changes for a period of 3 months prior to bariatric surgery and were followed for 1 year after surgery. The correlations between risk factors and weight reduction were assessed by a Pearson test.
RESULTS: Lifestyle changes resulted in a mean weight reduction of 14.3 kg. One year after bariatric surgery, the patients had a mean reduction in BMI of 17.6. Mean waist circumference was reduced from 136.5 cm to 100.7 cm. At baseline, all 40 patients had a waist circumference >100 cm; 1 year after surgery 18 of 40 patients did. At baseline, 11 out of 40 had insulin resistance (as defined by a homeostasis model score >3.99), whereas 1 year after surgery none of the patients did. There was a statistically significant correlation between change in waist circumference and change in insulin resistance (P<0.02), and between HbA1c and weight loss (P<0.002).
CONCLUSIONS: Our study shows that, in morbidly obese individuals, lifestyle changes followed by bariatric surgery led to a significant weight loss and a reduction in risk factors for development of T2DM.