medwireNews: People with obesity and type 2 diabetes who undergo gastric bypass surgery have higher rates of diabetes remission after 1 year than those undergoing sleeve gastrectomy, indicate findings from the Oseberg trial.
These results challenge “the common view that the surgical procedures yield similar results,” say Jøran Hjelmesæth (Vestfold Hospital Trust, Tønsberg, Norway) and co-investigators.
The study included 109 participants with an average BMI of 42.3 kg/m2 and a median diabetes duration of 5.0 years who were scheduled to receive bariatric surgery and randomly assigned to undergo one of the two procedures.
After 1 year of follow-up, individuals in the gastric bypass group had a significant 57% increased likelihood of achieving diabetes remission – defined as glycated hemoglobin (HbA1c) levels of 6.0% or lower without use of diabetes medications – compared with those in the sleeve gastrectomy group, at rates of 74% versus 47%.
Participants undergoing gastric bypass also experienced significantly greater loss in average bodyweight (36 vs 30 kg) and fat mass (52 vs 40%) relative to those in the sleeve gastrectomy arm, report the researchers in The Lancet Diabetes & Endocrinology.
Despite these positive results, the investigators found that beta-cell function, measured by the disposition index (the product of insulin sensitivity and acute insulin response to glucose), improved to a comparable degree in both groups, with a six- to eightfold increase observed.
Average levels of HbA1c also decreased to a similar degree in the gastric bypass and sleeve gastrectomy arms, with reductions of 2.0% and 2.2%, respectively.
These findings “could mean that there is no true difference between the procedures,” say Hjelmesæth et al, but they add that the lack of difference in beta-cell function between the groups “must be interpreted with caution” because it is possible that “other measures of insulin sensitivity and insulin secretion, including the assessment of the incretin effect, would have given different results.”
The study authors report similar rates of complications and adverse events among the two groups. For example, rates of symptomatic hypoglycemia were 19% and 13% in the gastric bypass and sleeve gastrectomy groups, respectively, while the corresponding numbers of late adverse events were 17 and 22.
Writing in an accompanying comment, Paul O’Brien (Monash University, Melbourne, Victoria, Australia) says that considering the Oseberg results alongside existing evidence, “gastric bypass should be considered the procedure of choice while we await longer follow-up data for confirmation that the difference in effect is durable.”
Nevertheless, he believes that “several issues require further investigation.” Pointing to the DiRECT study results, previously reported by medwireNews, which demonstrated that diabetes remission is possible with a primary care diet intervention, he questions whether “the effects on glycaemia [are] great enough to justify surgery, particularly with sleeve gastrectomy.”
He also emphasizes that “1 year of follow-up is clearly insufficient,” with follow-up results from the STAMPEDE study demonstrating “concerning” trends of weight regain and loss of diabetes remission.
Furthermore, “[l]ittle evidence is available on whether weight-loss surgery can reduce the complications of diabetes,” he says.
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