Bariatric surgery performed considerably better than traditional medical therapy for obese patients with type 2 diabetes, independent of weight loss, according to findings from 2 randomized trials published online March 26 in the New England Journal of Medicine.
"The unique ability of surgery to improve blood sugar levels and cholesterol levels as well as reduce weight makes it an ideal approach for obese patients with type 2 diabetes," lead author of one of the studies Geltrude Mingrone, MD, chief of the Division of Obesity and Metabolic Diseases and professor of medicine at Catholic University in Rome, Italy, said in a news release.
According to the World Health Organization, approximately 8.3% of the global population worldwide had type 2 diabetes in 2010, with a projected increase in prevalence to 9.9% by 2030.
Nearly one quarter (up to 23%) of patients with morbid obesity also have type 2 diabetes, and treatment is particularly challenging in these patients because insulin and other hypoglycemic agents often cause additional weight gain. Bariatric surgery may be cost-effective for obese patients with diabetes because of the tremendous healthcare burden associated with this chronic disease.
Catholic University Study
In the trial from Catholic University, 60 severely obese patients (body mass index [BMI], >35 kg/m2) aged 30 to 60 years with advanced type 2 diabetes mellitus were randomly assigned to treatment with Roux-en-Y gastric bypass (RYGB), bilopancreatic diversion (BPD), or conventional treatment. This last group had individualized medication therapy and strictly monitored diet and lifestyle interventions.
At baseline, patients had a history of diabetes for at least 5 years and hemoglobin A1c (HbA1c) levels of at least 7.0%. The main study outcome was remission, defined as fasting glucose less than 100 mg and HbA1c levels less than 6.5% for 1 year or longer, without use of diabetes medication.
Since the trial began, none of the patients in the medical group has entered remission, whereas 95% of patients in the BPD group and 75% of those in the RYGB group have entered and maintained remission for the 2-year study period and were able to discontinue all diabetes medications. Age, sex, preoperative BMI, duration of diabetes, and weight loss after surgery did not predict diabetes remission.
"These findings confirm that the effects of bariatric surgery on type 2 diabetes may be attributed to the mechanisms of surgery rather than the consequences of weight loss," Dr. Mingrone said in the release. "Studying the actual mechanisms by which surgery improves diabetes may help understand the disease better."
Most patients treated with bariatric surgery in this study had improvements in blood glucose and lipid profile, suggesting that this intervention may lower cardiovascular risk.