Bariatric intervention effective at reversing Type 2 diabetes
- Correspondence to: Luigi Meneghini
Department of Medicine, University of Miami Miller School of medicine, 1450 NW 10th Avenue, Miami, FL 33136, USA;
Commentary on: Google Scholar
Obesity is at worldwide epidemic proportions with estimates that over 60% of the population is overweight or obese in the USA.1 Individuals born in this decade have a 30–50% risk of developing diabetes over their lifetime,2 with potentially disastrous consequences from disease complications. Medical interventions to promote clinically meaningful weight loss are effort intensive, with most patients unable to achieve and maintain long-term weight loss. Bariatric surgery achieves more effective and sustainable weight loss and cardiovascular benefits than medical therapy.3 It is more effective at improving diabetes control and inducing disease remission than conventional medical therapy.4 It is recommended as a treatment option in selected obese individuals with Type 2 diabetes.5
This single site, open label, randomised 12-month study compares intensive medical therapy (IMT) with or without the addition of a surgical bariatric intervention (Roux-en-Y gastric bypass (GBP) or sleeve gastrectomy (SG)) in 150 obese patients with poorly controlled Type 2 diabetes. The primary end-point was the proportion of patients with an A1C≤6.0% 12 months after treatment. Complete data were available on 140 patients (93%) with nine patients lost from the IMT group, and one who did not undergo the sleeve gastrectomy. Perprotocol analysis was performed.
Impressive results were achieved by IMT (mean A1C reduction of 1.4% with a concomitant mean weight loss of 5.4 kg). Surgical intervention complementing IMT resulted in a greater proportion of patients achieving the primary end-point of an A1C≤6% at 12 months (42% and 37% vs 12% in the GBP, SG and IMT, respectively). All of the GBP patients that achieved the primary end-point did so without the need for antidiabetic medications. The significantly greater weight loss following the bariatric procedures (−29.4 and −25.1 vs −5.4 kg for the GBP, SG and IMT, respectively) resulted in a reduction in medication use for control of lipids and blood pressure, as well as a greater improvement in markers of metabolic syndrome and inflammation. Clinical gains were most evident in the first 3 months following surgery and were retained throughout the 12 months of the study. The only significant adverse event reported was a need for additional surgical intervention in four patients.
The strengths of the reported study include: the rigorous assessments of dysglycaemia, the comprehensive approach to patient treatment according to published standards of medical care, the substantial improvement in clinical outcomes in the IMT group, the use of a single, experienced surgeon to perform the bariatric procedures and the plan for an additional 4 years of follow-up. The inclusion of patients with a body mass index (BMI)<35 kg/m2 (representing 28–38% of the randomised subjects) and advanced diabetes (mean disease duration >8 years, microvascular complications present in 14–29% of patients, 44% of patients using insulin and elevated baseline A1C) provides additional information regarding the generalisable applicability of bariatric intervention. Study limitations included the short duration of reported follow-up and the open-label, single-centre nature of the study.
This trial adds to the growing knowledge regarding bariatric intervention, with a more specific focus on the impact of such procedures on diabetes and related comorbidities, as reflected by the inclusion of subjects with BMI between 27 and 43 kg/m2. The rates of diabetes resolution are not as high as those in previously reported studies, owing to a population with more advanced disease. A review of the appendix (see supplementary table S5) appears to indicate that patients achieving an A1C≤6% were more likely to have had a higher BMI and shorter diabetes duration. This study also adds additional knowledge to the use of a bariatric intervention in patients with a BMI that is lower than the threshold currently recommended for surgical consideration,5 although it would have been informative to have additional outcomes stratified according to BMI.
Long-term outcomes in patients who have undergone a bariatric procedure demonstrate reduced mortality as a result of a decrease in cardiovascular disease and cancer rates.6 Given that patients with diabetes carry an even greater risk for atherosclerosis and cancer, it will be of particular importance to understand if the metabolic improvements in this population of people with diabetes will also translate into similar long-term benefits.