More than 10 million Americans have diabetes and 95%of these have Type II Diabetes Mellitus, T2DM. There is no known medical cure for T2DM and the disease is generally progressive, with development of retinopathy, renal failure, hypertension and peripheral vascular disease. Current therapies (insulin, diet, exercise, oral agents) have not been shown to prevent the development of these complications. In addition, 30-50% of patients with impaired glucose tolerance, IGT, will progress to T2DM within 10 years.
Two studies from East Carolina University looked specifically at the effect of gastric bypass for morbid obesity in patients with T2DM and IGT. 83% of patients with T2DM (121/146) achieved normal levels of plasma glucose, glycosylated hemoglobin and insulin. Complete control of glucose metabolism was also achieved in 99% of patients with IGT (150/152). Mean follow-up was 7.6 years, with a range of 1-14 years (158 patients followed for more than 10 years). Only two patients with IGT, out of 152, progressed to T2DM. Far fewer than the number (between 43 and 75 patients) who would have developed T2DM with standard management.
Normalization of glucose metabolism occurs remarkably fast after gastric bypass. An example was a patient with a fasting blood glucose level of 495 mg/dl prior to surgery, despite 90U of insulin the day prior to surgery. By the 6th postoperative day she no longer required insulin. Her fasting blood sugar was 155 mg/dl one month after surgery, and normal by post-op month 3. Of the total 298 patients, 35 episodes of hypoglycemia were identified. These mostly corrected spontaneously within one year. Patients we instructed to carry sugar for symptomatic relief and no patient ever required medical intervention for hypoglycemia.
These important results are underscored in the second study, which compared 78 morbidly obese patients with T2DM who were managed non-surgically with 154 similar patients managed by gastric bypass. Mean patient age, BMI, weight and sex were the same between the two groups. Length of follow-up was 9 years in the surgical group and 6.2 years in the non-surgical group. During the follow up period, the number of patients requiring oral hypoglycemic agents or insulin fell from 32% to 9% in the surgical group and increased from 56% to 88% in the non-surgical group. Cardiovascular death occurred in 12 of 78 non-surgical patients (15.4%) within 6 years and only 2 of 154 (0.7%) of surgical patients over 9 years. More dramatically, the non-surgical group had a mortality of 28% while the surgical group had a mortality of only 9%. Correcting for the longer follow-up in the surgical group, the annual mortality was 4.5 times higher in the non-surgical group.
These studies are very dramatic. They demonstrate the progressive, and often irreversible, nature of Type II Diabetes as well as the ability of gastric bypass to prevent this progression and to provide a long term cure for this devastating disease in patients with morbid obesity.
MacDonald, K.G., et al; The Gastric Bypass Operation Reduces the Progression and Mortality of Non-Insulin-Dependent Diabetes Mellitus. J Gastrointest Surg 1997
Poires, W.J., et al; Who Would Have Thought It? An Operation Proves to Be the Most Effective Therapy for Adult-Onset Diabetes Mellitus