Three-Year Outcomes of Bariatric Surgery vs Lifestyle Intervention for Type 2 Diabetes Mellitus Treatment: A Randomized Clinical Trial

Abstract

Importance: Questions remain about the role and durability of bariatric surgery for type 2 diabetes mellitus (T2DM).

Objective: To compare the remission of T2DM following surgical and nonsurgical treatments.

Design, setting, and participants: In this 3-arm randomized clinical trial conducted at the University of Pittsburgh Medical Center from October 1, 2009, to June 26, 2014, in Pittsburgh, Pennsylvania, outcomes were assessed 3 years after treating 61 obese participants aged 25 to 55 years with T2DM. Analysis was conducted with an intent-to-treat population.

Interventions: Participants were randomized to either an intensive lifestyle weight loss intervention for 1 year followed by a low-level lifestyle intervention for 2 years or surgical treatments (Roux-en-Y gastric bypass [RYGB] or laparoscopic adjustable gastric banding [LAGB]) followed by low-level lifestyle intervention in years 2 and 3.

Main outcomes and measures: Primary end points were partial and complete T2DM remission and secondary end points included diabetes medications and weight change.

Results: Body mass index (calculated as weight in kilograms divided by height in meters squared) was less than 35 for 26 participants (43%), 50 (82%) were women, and 13 (21%) were African American. Mean (SD) values were 100.5 (13.7) kg for weight, 47.3 (6.6) years for age, 7.8% (1.9%) for hemoglobin A1c level, and 171.3 (72.5) mg/dL for fasting plasma glucose level. Partial or complete T2DM remission was achieved by 40% (n = 8) of RYGB, 29% (n = 6) of LAGB, and no intensive lifestyle weight loss intervention participants (P = .004). The use of diabetes medications was reduced more in the surgical groups than the lifestyle intervention-alone group, with 65% of RYGB, 33% of LAGB, and none of the intensive lifestyle weight loss intervention participants going from using insulin or oral medication at baseline to no medication at year 3 (P < .001). Mean (SE) reductions in percentage of body weight at 3 years were the greatest after RYGB at 25.0% (2.0%), followed by LAGB at 15.0% (2.0%) and lifestyle treatment at 5.7% (2.4%) (P < .01).

Conclusions and relevance: Among obese participants with T2DM, bariatric surgery with 2 years of an adjunctive low-level lifestyle intervention resulted in more disease remission than did lifestyle intervention alone.

Trial registration: clinicaltrials.gov Identifier: NCT01047735.

Figure 1. Prevalence of any remission (partial or complete) by treatment group and year

^aPartial remission of T2DM - no use of antidiabetics, hemoglobin A1c (HbA1c) level of less than 6.5%, and fasting plasma glucose (FPG) level of125 mg/dL or less Complete remission of T2DM - no use of antidiabetics, HbA1c level of less than 5.7%, and FPG level of 100mg/dL or less Missing data at follow-up were assumed to be no remission. RYGB = Roux-en-Y gastric bypass, LAGB = laparoscopic gastric banding, LWLI = Lifestyle weight loss intervention (intensive) The test of the difference between treatment group p-values are calculated for each time point as follows: year 1 p = <0.0001, year 2 p<0.0001, year 3 p = 0.0037.

Figure 2. Hemoglobin A1c (HbA1c) and Fasting Plasma Glucose (FPG) change by treatment group and year

^aBars represent standard error

Figure 3. Diabetes medication usage by treatment group

^aBaseline n=20; Year 1; n=18; Year 2 n=18; Year 3 n=18 ^bBaseline n=21; Year 1 n=19; Year 2 n=17; Year 3 n=20 ^cBaseline n=20; Year 1 n=14; Year 2 n=14; Year 3 n=14* *One participant was missing medication data

Figure 4. Percent weight change from baseline by treatment group^a

^aModeled data, Bars represent standard error (SE)