Adults who have obesity and type 2 diabetes are much more likely to see their diabetes stay in remission if they undergo gastric bypass surgery rather than sleeve gastrectomy, even after regaining weight, according to researchers from the Mayo Clinic in Rochester, MN. The study authors said the concurrent weight-loss independent metabolic benefit is likely facilitated by bypassing the proximal small-intestine.
"We showed that in patients who had bariatric surgery, bypassing the duodenum has a greater benefit for patients with diabetes. We saw that patients who had sleeve gastrectomy and weight recurrence had a much greater chance of having their diabetes return when compared to their gastric bypass counterparts, even after adjusting for all diabetes patient factors," said lead study author, Dr Omar M Ghanem, a bariatric and metabolic surgeon at the Mayo Clinic. "We know that the first portion of the intestine, the duodenum, plays a very important part of digestion, and helps regulate what we call the 'gut metabolic pathway.' Bypassing that axis contributes to many physiologic actions or changes in metabolism and one of them is the regulation of glycemia and eventually diabetes.”
For the study, researchers investigated whether diabetes returned when patients regained their weight after bariatric surgery. The review was based on data from 224 patients who underwent gastric bypass surgery and 46 control subjects who underwent sleeve gastrectomy at Mayo Clinic between 2008 and 2017.
All patients involved in the analysis had obesity and had been diagnosed with type 2 diabetes before they underwent weight loss surgery. Each patient was followed for at least five years after the operation. Diabetes remission rates were then grouped into four weight relapse categories and compared. The aim was to see if weight gain led to diabetes recurrence.
Key findings of the study included:
Overall, 75% of gastric bypass patients saw their diabetes stay in remission, compared with only 34.8% of patients in the sleeve gastrectomy group.
After adjusting for patient and weight-related factors, the odds of diabetes returning over the five-year follow-up period were 5.5 times greater in the sleeve gastrectomy group compared to the gastric bypass group.
In a subgroup analysis of gastric bypass patients, diabetes remission rates were stratified into four weight regain categories. Over half of the patients in all four categories (patients who lost weight after surgery and regained 25%, 25% to 50%, 50% to 75%, and more than 75% of the weight they initially lost from having surgery) kept their diabetes in remission.
Among patients who regained 100% or more of their weight after gastric bypass surgery, about 60% kept their diabetes in remission five years after the operation, compared to zero in the gastric sleeve group.
Insulin use, higher preoperative A1c (which measures average blood sugar levels), and longer preoperative duration of diabetes were associated with diabetes recurrence, whereas weight regain was not.
"These findings help us understand how the bypass works and how to keep diabetes in remission. Looking forward, we need to understand the mechanism behind this association so we can counsel patients on the best procedure for them when presenting to us with diabetes," added Ghanem. "A major determining fact when choosing the most appropriate surgery is if the patient wants to eliminate diabetes or wants to have the least chance of having diabetes come back in the long term. While both procedures are great, we know that gastric bypass is a better procedure for patients with diabetes at this point."
A potential limitation of the study is that it is a retrospective, single-centre study. Therefore, the results may not apply to other bariatric programs across the country.
"Diabetes remission is more durable after gastric bypass than after sleeve gastrectomy. The magnitude of the difference in this study is important," said Dr Anthony T Petrick, director, division of bariatric and foregut surgery, Geisinger Health System, who was not involved with the study. "Although there was a small number of sleeve gastrectomy patients in this study, the long-term follow-up is a strength of these findings."
The researchers noted they intend to conduct more in-depth studies to understand this connection on a cellular level, which will better explain these findings.
The findings were reported in paper, ‘Continued Diabetes Remission Despite Weight Recurrence: The Gastric Bypass Long-Term Metabolic Benefit’, published in the Journal of the American College of Surgeons. To access this paper, please click here (log-in maybe required)