Five-Year Data Shows Surgery Achieves Better Long-term Control for Diabetes

Bariatric surgery is more effective than standard medical treatment for the long-term control of type 2 diabetes in obese patients, according to a recent study in The Lancet. This is the first study to examine five-year outcomes data of surgery compared with standard therapy in this cohort. 

Previous studies have shown that bariatric surgery is more effective than conventional treatment for the short-term control of type 2 diabetes. However, no studies yet have provided information on longer-term outcomes. 

The open-label, single-center, randomized, controlled study, led by Geltrude Mingrone, MD, Catholic University of the Sacred Heart (Rome, Italy), and colleagues followed 60 patients aged 30–60 years with a body mass index of ≥35 kg/m2, a history of diabetes lasting at least 5 years, and hemoglobin A1c (HbA1c) of ≥7%. Patients were randomized 1:1:1 to receive medical treatment (n=20) or surgery by Roux-en-Y gastric bypass (n=20) or bilipancreatic-diversion surgery (n=20). The primary endpoint was the rate of diabetes remission at 2 years, defined as a fasting glucose concentration of 5.6 mmol/L or less and HbA1c of 6.5% or less without active drug treatment for at least 1 year. At the 5-year follow-up, the researchers looked at various secondary endpoints including durability of diabetes, overall glycemic and metabolic control, cardiovascular risk, medication use, quality of life, and long-term surgical outcomes.

Overall, diabetes remission at 5 years was observed in 19 of 38 (50%) patients who had surgery compared with 0 of 15 patients who received medical treatment. Of the patients in remission, 7 (37%) had underwent gastric bypass and 12 (63%) had underwent bilipancreatic diversion. Of patients who achieved 2-year remission with surgery, 53% of those who underwent gastric bypass and 37% of those who underwent bilipancreatic diversion later relapsed with hyperglycemia. However, these patients maintained a mean HbA1c of 6.7% at 5 years with only diet and either metformin or no medication. Both surgical procedures resulted in greater weight loss than did medical treatment, but changes in weight did not predict diabetes relapse or remission following surgery. Patients in the surgical group also had significantly lower plasma levels and used significantly fewer cardiovascular drugs and antidiabetes medications. The estimated cardiovascular risk at 5 years was roughly half that of patients receiving medical treatment. Surgery was also associated with improved quality of life scores.

As for risk–benefit profile, there were no major long-term complications or mortality after the surgery. Nutrient-deficiency side effects were experienced by more patients who underwent bilipancreatic diversion surgery than those who underwent gastric bypass surgery. The researchers acknowledged that the study only included a small number of patients and was a single-center study.

Results from this study “support consideration of surgery in the treatment algorithm for type 2 diabetes,” wrote the authors, noting that continued monitoring of glycemic control is warranted due to potential relapse of hyperglycemia.—Eileen Koutnik-Fotopoulos

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Mingrone G, Panunzi S, De Gaetano A, et al. Bariatric-metabolic surgery versus conventional medical treatment in obese patients with type 2 diabetes: 5 year follow-up of an open-label, single-centre, randomised controlled trial. Lancet. 2015;386(9997):964-973.