Background/Aims – Many reports have suggested that bariatric surgery (BS) can produce a complete and durable remission of type 2 diabetes mellitus (T2DM). Our aim was to examine the long-term patterns of T2DM remission and relapse among severely obese adults who did and did not undergo BS.
Methods – We conducted a retrospective cohort study of adults with uncontrolled or medication-controlled T2DM who underwent BS in three health care systems in the HMORN from 1995-2008. A second comparison cohort included all adults with severe obesity (BMI >=35) and uncontrolled or medication-controlled T2DM from 2005-2008 (years BMI data were available from electronic medical records). Our main outcomes of interest were remission and relapse of T2DM, which were defined using pharmacy and laboratory data. We used a novel propensity approach to identify a final sample for our comparative effectiveness analyses, and we chose a multivariable-adjusted Cox proportional hazards framework to investigate the impact of BS vs. usual care on diabetes remission.
Results – We identified 4,353 adults with uncontrolled or medication-controlled T2DM who had BS from 1995-2008. Most procedures were Roux-en-Y gastric bypass (RYGB; 53.6% open; 42.8% laparoscopic); 1.8% were gastric banding, and 1.8% were other procedures. Overall, 80.0% experienced an initial T2DM remission within five years after BS. Among those who initially remitted, 36.7% went on to redevelop T2DM within five years. The median duration of T2DM remission was 7.5 years. Significant predictors of remission and relapse were procedure type, poor preoperative glycemic control, insulin use, and longer duration of T2DM. After applying our propensity approach, our comparative effectiveness sample comprised 1,395 BS subjects and 62,167 non-surgical subjects from 2005-2008. The bariatric subjects experienced T2DM remission at a significantly higher rate [Hazard Ratio: 18.7; 95% Confidence Interval: 17.1 to 20.4].
Conclusions – BS is associated with durable remission of T2DM in many, but not all severely obese adults, with about one-third experiencing a relapse within five years. The BS approach appears far superior to usual medical care for T2DM remission; however, given the rate of relapse, caution should be advised in recommending BS as a “cure” for T2DM in severely obese patients.