Efficacy in type 2 diabetes mellitus remission in patients undergoing bariatric surgery

To assess remission of type 2 diabetes mellitus (T2DM) after bariatric surgery, to analyze potential conditioning factors, and to compare Spanish and American remission criteria.

A retrospective study of diabetic patients undergoing Roux-en-Y gastric bypass from 2009 to 2015. Data collected included age, sex, time since T2DM diagnosis, antidiabetic drugs, insulin (type and dose), weight and BMI, percent excess weight lost, HbA_1c, blood glucose levels, and course of T2DM after surgery according to Spanish and American criteria, including a descriptive analysis and correlation between both.

The study sample consisted of 106 patients. Outcomes one year after surgery was as follows (Spanish criteria): complete remission 65.9%, partial remission 5.5%, improvement 18.9%, no change 9.7% (at 5 years: 68.4, 5.3, 10.5, and 15.8%, respectively). Outcomes according to ADA criteria were as follows: complete remission 61.5%, partial remission 5.3%, and no remission 28.6% (after 5 years, complete remission 68.4%). There was a good correlation between both classifications (Rho=0.974; P<.001). Mean HbA_1c levels: 7.3±1.8% at baseline; 5.7±1% at one year; 6.3±1.2% at 5 years. Chance of remission was lower in patients aged over 50 years (54.4 vs. 88.2%; P=.001), with T2DM diagnosed more than 10 years before (26.3 vs. 81.8%; P<.001), on insulin treatment (31.3 vs. 87.9%; P<.001), and with HbA_1c levels≥8% (40 vs. 77%; P=.001).

At our hospital, bariatric surgery is associated to a high remission rate of T2DM in patients with morbid obesity, with a good correlation between Spanish and American criteria. Age over 50 years old, long T2DM duration, poorer baseline metabolic control, and previous insulin treatment are markers of poorer response.