Bariatric Surgery vs Lifestyle Intervention for Diabetes Treatment

5-Year Outcomes From a Randomized Trial

Anita P. Courcoulas; James W. Gallagher; Rebecca H. Neiberg; Emily B. Eagleton; James P. DeLany; Wei Lang; Suriya Punchai; William Gourash; John M. Jakicic


J Clin Endocrinol Metab. 2020;105(3) 

In This Article


The results of this study show that at 5-year follow-up RYGB + LLLI was the most effective treatment, followed by LAGB plus LLLI, for T2DM remission and other glycemic control endpoints. Remission rates for T2DM declined over the 5 years of the study but were greatest for RYGB. Nearly 60% of those in the RYGB group and half of the LAGB group did not require any medications for T2DM treatment at 5 years compared with none of those in the lifestyle intervention-only group. The surgical intervention groups both had significantly higher probability of achieving and maintaining glycemic control when compared with the intensive lifestyle therapy alone group, in people with both class I and II obesity in this study. The safety of the procedures was acceptable with no deaths and very few adverse events overall in both surgical groups and the lifestyle-only group. Secondary outcomes of this study, including body weight, blood pressure, and lipids, also demonstrated the greatest improvements in the RYGB group, followed by LAGB then LWLI.

Three other RCTs with 5-year results comparing surgical with nonsurgical treatments have been published.[3,4,7] In the study by Mingrone et al., 60 patients who underwent biliopancreatic diversion (BPD) or RYGB were compared with a medical treatment group. The remission rate of T2DM (FPG level of less than 100 mg per deciliter (5.6 mmol/L) and a glycated hemoglobin level of less than 6.5% for at least 1 year without active pharmacologic therapy) was 63% in BPD group, 37% for RYGB, and none in the medically treated patients.[16] However, relapse of diabetes occurred in 37% of BPD patients and 53% of RYGB patients who had achieved 2-year remission.[16] There was one fatal myocardial infarction in the medical arm and no late complications or deaths occurred in the surgery groups and nutritional side-effects were noted mainly after biliopancreatic diversion.[7] Further, Schauer et al. reported 5-year outcomes comparing RYGB or sleeve gastrectomy (SG) to intensive medical therapy alone. Their results showed a remission of T2DM (HbA1C ≤ 6.0%, on or off medications) in 29% of RYGB, 23% SG, and 5% of nonsurgical patients.[3] If the criterion to be off glycemic control medications was added in the Schauer study, the remission rate dropped to 22% RYGB, 15% SG, and 0% for medical therapy with a good safety profile for all groups. In the multicenter trial by Ikramuddin et al. comparing RYGB to medical treatment with a triple primary endpoint, 13 participants (23%) in the gastric bypass group and 2 (4%) in the lifestyle-intensive medical management group had achieved the composite triple end point and 31 patients (55%) in the gastric bypass group versus 8 (14%) in the lifestyle-medical management group achieved an HbA1c level of less than 7.0%. The surgery group had more serious adverse events than did the lifestyle–medical management intervention in that trial and most were gastrointestinal events and surgical complications such as strictures, small bowel obstructions, and leaks.[4] It is clear from these 3 other longer-term RCTs that the definitions of diabetes remission varies between studies, making direct comparisons difficult. Nevertheless, the remission rate in this study was similar to that of the RYGB group in the Mingrone study at 5 years with comparable remission definitions. The results of the current study are also comparable to the Schauer and Ikramuddin reports, given the different thresholds used for remission of diabetes.

As summarized at a recent World Conference on Interventional Therapies for Diabetes (WCITD)[17] there are currently 874 patients in total included in randomized studies comparing bariatric/metabolic surgery to nonsurgical treatment worldwide; 3 published studies with 5-year follow-up, 3 published studies with 3-year follow-up (including this one), and several with 1- to 2-year follow-up. All except one, show superiority of surgical to medical treatment for T2DM treatment consistent with the current additional 5-year data from this study.[18,19] In all these studies, including the current one, the remission rates for T2DM with surgery do decrease with increasing follow-up. In the WCITD summary, there were very few cardiovascular events or deaths in either surgical or medical group and the most common adverse events after bariatric surgery were anemia (15%), gastrointestinal disturbances (5–10%), and reoperation (8%). The rates of adverse events in the current study were also low, consistent with the WCITD summary.

Also, of note was a broader enrollment for people with varying diabetes severity in our study, with an initially lower average baseline HbA1c in our cohort of 7.8 ± 1.9%, versus 9.2 ± 1.5% in the Schauer trial and over 8.0% in the Ikramuddin study. Our study also included a large proportion of people (40%) with a BMI of 30 to 35 kg/m2 (class I obesity), for whom data are still lacking, thus contributing to filling that gap in knowledge. The results from this study continue to support the literature and algorithm for considering bariatric/metabolic surgery as an alternative treatment for people with class I obesity and T2DM in whom medical management is unsuccessful in achieving glycemic control.[5]

This study is also the first RCT with 5-year results that include the LAGB as a surgical treatment group. The use of LAGB has declined dramatically worldwide,[20] but the LAGB may still have a limited role for the management of selected lower BMI/class I obesity patients as results for glycemic control are superior to nonsurgical treatment in this trial. There are also a few previous RCTs utilizing LAGB which have reported results at 2 years after surgery and demonstrated about 20% initial weight loss.[21,22] The results from the current study demonstrate less weight loss (12.7%) at 5 years and a remission rate for T2DM of 19% at 5 years. The LAGB diabetes remission rate in this study is somewhat lower than results from the Longitudinal Assessment of Bariatric Surgery Study, which was an observational, multicenter study in the United States that showed significant heterogeneity of weight loss (median, 15%) and 29% T2DM remission at the 5-year timepoint for LAGB.[23]

This study has several strengths including a relatively large proportion of participants with class I obesity, therefore expanding the evidence within this specific population. We show a detailed collection of all adverse and other events with a low rate of reoperation and complications in the longer term. These results may be more generalizable to people with obesity and various degrees of T2DM severity due to inclusion of people with lower average baseline HbA1c in this study. A limitation of this study may be in the behavioral approach that was undertaken in LWLI. This study implemented a behavioral intervention that was based primarily on the approach from the Look AHEAD Study, which included modest energy restriction, physical activity, and behavioral counseling. This approach was shown to result in weight loss, enhanced glycemic control, and reduction in medication usage compared with diabetes support and education intervention. However, this approach may not be effective for all participants undertaking a LWLI. Thus, other dietary or physical activity approaches focused on weight loss and glycemic control in patients with type 2 diabetes may warrant examination for comparison with bariatric surgery. Additional limitations of this study include the small sample size in a single center, which may affect generalizability. However, larger RCTs are unlikely to be carried out due to the significant financial costs of such trials and the great difficulty with recruitment into surgical vs medical treatment trials, as seen in the first phase of this trial and other feasibility trials.[10,24,25] Given these obstacles to a large trial, the alternative is to pool the data from smaller trials together into a larger study which has been done in forming the Alliance of Randomized Trials of Medicine vs Metabolic Surgery in Type 2 Diabetes Collaborative.[3,8,9,26,27] This study will pool the data from four separate and smaller trials (including this one) to yield 7 to 10 year durability and safety results on approximately 300 people with class I and II obesity who underwent randomization to surgical and medical/lifestyle treatments.

In conclusion, surgical treatments including RYGB and then LAGB are safe and more effective than lifestyle intervention alone for long-term diabetes remission and glycemic control in people with obesity, including those with a BMI between 30 and 35 kg/m2. Bariatric surgery should be considered in the treatment algorithm for type 2 diabetes treatment for all obesity classes.