Type 2 diabetes may recur after gastric bypass surgery, study finds

Type 2 diabetes may recur in a significant proportion of patients who undergo gastric bypass surgery, a new study has found.

Researchers performed a retrospective cohort study among adults with type 2 diabetes, uncontrolled or controlled by medication, who had gastric bypass surgery (Roux-en-Y) at three U.S. integrated health care delivery systems between 1995 and 2008. The study's goal was to determine long-term remission and relapse rates of type 2 diabetes after gastric bypass, as well as clinical predictors. The researchers defined remission and relapse events according to use of diabetes medications (a current prescription at the time of surgery) and laboratory-measured glycemic control (hemoglobin A1c level ≥6.5% at the most recent measurement before surgery). The study results were published online Nov. 18 by Obesity Surgery.

A total of 4,434 adults, 77.1% women, met the study criteria. The average age of the study population was 49.6 years. Overall, 2,254 had complete remission of their diabetes within five years of gastric bypass surgery. Of this group, the authors report more than one-third developed diabetes again within five years of remission (median remission duration, 8.3 years). Complete remission was defined as discontinuation of diabetes medication plus fasting glucose levels below 100 mg/dL and/or hemoglobin A1c levels below 6.0% at least 90 days after the last filled prescription for diabetes medication ended. Relapse was defined as resuming a diabetes medication, having at least one hemoglobin A1c value of 6.5% or more, and/or having at least one fasting glucose measure of 126 mg/dL or more. Patients who had poor glycemic control before surgery, used insulin or had had diabetes longer were more likely to have remission and relapse. In an analysis of the 47% of the total sample who had available data on body mass index, the authors found that weight loss patterns after surgery differed according to whether patients had no diabetes remission, had remission and later relapsed, or remained in remission (P=0.03).

The study could not take variations in surgical technique into account and did not have enough data to analyze outcomes according to such factors as race/ethnicity or diabetes-related mortality, among other limitations. The researchers concluded that based on their results, a substantial proportion of patients do not experience lasting remission of diabetes after gastric bypass surgery and that “patients should be counseled that bariatric surgery alone does not reliably ‘cure’ diabetes.” They noted, however, that “the remission rates achieved by [gastric bypass surgery] appear to be far better than what could be achieved by any other behavioral treatment.” The authors also pointed out that bariatric surgery seemed to have the most lasting effect in patients with recent diabetes, and they called for further studies to help confirm these findings.