Fasting insulin and glucose reductions predicted by degree of weight loss after surgery, study reports

The degree of weight loss is more important for achieving long-term reductions in fasting insulin and glucose than choice of weight loss surgery, a Swedish study reports.
Weight loss (bariatric) surgery is generally considered an extreme measure, but in September 2015, a study found that bariatric surgery led to prolonged remission in half of patients with type 2 diabetes for at least five years.
The National Institute for Health and Care Excellence (NICE) recommend that anybody who is classified as obese, or recently diagnosed with type 2 diabetes or a weight-related illness could be considered for surgery.
In this new study, researchers at the University of Gothenburg analysed data from the Swedish Obese Subjects study, comparing the weight change-adjusted effects of gastric bypass to restrictive surgical procedures on long-term changes in fasting glucose, insulin and insulin resistance.
1,762 patients completed the two-year follow-up, while 1,126 patients completed the 10-year follow-up. They were divided into three weight changes classes (weight loss greater than 30 per cent, 20-30 per cent or 20 per cent) and method of surgery (gastric banding, vertical banded gastroplasty and gastric bypass).
Weight loss of more than 30 per cent was more common in the gastric bypass group compared to the other two surgical methods, and reductions in insulin resistance and fasting levels of glucose and insulin increased among those who had lost the most weight.
However, the association between weight change and adjusted glucose, insulin and levels of insulin resistance did not differ between the surgery groups at two and 10 years.
The researchers wrote: “Given the same degree of weight loss after bariatric surgery, there was no support for weight loss-independent benefits of [gastric bypass] over restrictive procedures on fasting glucose and insulin levels or [insulin resistance] over 2 and 10 years.
“Hence, even though weight loss-independent effects that differ between surgical procedures are important for short-term remissio, our results suggest that degree of weight loss is more important for long-term reductions in fasting insulin and glucose than choice of bariatric surgery procedure.”
The findings were published in the online journal Diabetes Care.