Diabetes remission off medications is not a suitable endpoint for comparing bariatric/metabolic surgery with pharmacotherapy

Excerpt

To the Editor: In their publication in Diabetologia, Cummings et al [1] describe how they used a randomised trial to compare the best available intensive lifestyle and medical intervention (ILMI) against Roux-en-Y gastric bypass (RYGB), and concluded that surgery achieved greater type 2 diabetes remission in mildly to moderately obese patients. However, mean HbA_1c values were not statistically different between groups at the end of study, which was not explicitly stated in the abstract. An OR for diabetes remission (defined as HbA_1c <6.0% [<42.1 mmol/mol], off all diabetes medicines) of almost 20 looks quite impressive, but in our opinion this is not a suitable study endpoint for analysis. Given that the comparison group received intensive lifestyle with optimal medical intervention, and therefore the very point of the intervention was the use of medication, it seems inappropriate that a criterion of the primary endpoint of interest was whether or not the patient was off medication. It is well established that diabetes is a chronic disease and most patients are unable to control their diabetes with intensive lifestyle interventions (the same applies to obesity itself, despite being associated with greater and persistent stigma). Therefore, the discontinuation of several classes of medications for type 2 diabetes would give rise to disease deterioration. As expected with any other chronic disease, the control group could be well controlled, but, of course, on medication. Since a surgical procedure can be considered a chronic treatment for diabetes (because the anatomical changes are permanent), this seems to be an unfair comparison. We believe that a better judgment (which still would favour surgery in the great majority of cases) would be an HbA_1c target that was independent of medication use. We acknowledge that the criteria for remission were not developed solely for this article and are being used in most bariatric/metabolic surgery studies, but because of the conclusion of the abstract and the absence of statistically significant differences in HbA_1c at the end of the treatment, this comment seems appropriate at this point. …