In addition to losing more weight, those who had weight-loss surgery had a rate of remission of type 2 diabetes that was 22 times higher than in the group that did not get surgery. Rates of metabolic syndrome also dropped more for those who had surgery, according to the analysis.
Triglycerides, a type of blood fat, dropped more, and levels of the good cholesterol (HDL) increased more for those who had surgery.
There were no significant differences in blood pressure levels and bad cholesterol (LDL) levels between the two groups, the investigators found.
"The evidence beyond two years of follow-up, in particular adverse events, cardiovascular diseases and mortality, remains unclear and calls for further research on the topic," noted Gloy.
Dr. Joel Zonszein, director of the clinical diabetes center at Montefiore Medical Center in New York City, said: "Weight gain is very easy, but to lose weight is very difficult. This was a careful meta-analysis, and I agree with what they've found. We don't yet understand exactly how bariatric surgeries cause remission of type 2 diabetes," he pointed out.
Another expert said weight-loss surgery should be happening more often.
"Bariatric surgery is underutilized. If we were talking about any other treatment with such a striking effect on diabetes, it would be offered to patients sooner," said Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City.
Of course, like any surgery, weight-loss surgeries don't come without risk. The most common complications reported in the current analysis were iron deficiency anemia and the need for re-operation. The surgery is also expensive. The U.S. National Institute of Diabetes and Digestive and Kidney Diseases estimates that weight-loss surgery averages as much as $25,000.
Roslin and Zonszein both said that people undergoing weight-loss surgery need to be carefully chosen. Current recommendations recommend the surgery for anyone with a body mass index (BMI) above 40, or a BMI of 35 or higher if they have other conditions related to obesity, such as type 2 diabetes or high blood pressure. BMI is a measurement based on height and weight.