WEDNESDAY, Aug. 5, 2015 (HealthDay News) -- Although weight-loss surgery may produce initial dramatic weight loss and improve type 2 diabetes, a new study suggests that in the long run, many people regain weight and see their diabetes return.
In fact, in the first year after an operation called sleeve gastrectomy, patients lost 77 percent their excess weight. But by the fifth year they regained weight, bringing their weight loss to only 56 percent. Also, 51 percent of patients saw type 2 diabetes disappear in the first year. By the fifth year, only 20 percent were still free of type 2 diabetes, researchers said.
"Weight-loss surgery is not a panacea for weight loss over the long run," said lead researcher Dr. Andrei Keidar, of the Beilinson Hospital in Petah Tikva, Israel.
Keidar said several reasons account for weight gain after surgery. "The main reason is that the stomach dilates, meaning you can eat more. The appetite comes back so patients can eat more and they want to eat more," he said.
Weight-loss surgery is a "behavioral surgery," Keidar said. "If you don't change your behavior, you are going to regain weight."
For the study, Keidar's team collected data on almost 450 operations done between April 2006 and February 2013. By the fifth year after surgery, however, only 39 people had full follow-up data.
The researchers also found that throughout the five years, 46 percent of the patients experienced a drop in blood pressure. Changes in cholesterol, however, were insignificant, they said.
Several weight-loss procedures are available. This study looked specifically at laparoscopic sleeve gastrectomy, which is becoming a more common procedure, researchers said.
During a sleeve gastrectomy, surgeons remove most of the stomach and create a long, slender pouch, or sleeve, from the remaining portion of the stomach, according to the U.S. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Reducing the size of the stomach limits the amount of food you can eat.
Removing most of the stomach also causes changes in gut hormones, suppresses appetite, lowers blood sugar and may make you feel fuller longer, according to the NIDDK.
Despite the weight gain and the return of diabetes, Keidar believes surgery is still the best hope obese patients have. "The results are still better with surgery than from diet programs or other treatments," he said.
The report was published Aug. 5 online in JAMA Surgery.
Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City, said, "After surgery the metabolic rate goes down and that opposes weight loss, so you can be eating significantly less than you used to and begin to regain weight. No matter what the operation is, the body wants to go back to its original weight."
Dr. Anita Courcoulas, chief of the Section of Minimally Invasive Bariatric and General Surgery at the University of Pittsburgh School of Medicine, said, "There are still critical gaps in knowledge about the long-term results of bariatric surgery."
In most bariatric surgery studies, including this one, the rates of complete follow-up of patients are low, she said. For example, in this study only 49 percent of people provided data three years after surgery.
"This means that people who do not return to their surgeon or medical center may have different experiences and/or different results from those who do," said Courcoulas, who wrote an accompanying journal editorial.
Five years after sleeve gastrectomy, people regain weight and fewer remain free from type 2 diabetes, she said.
"This implies that longer-term and more complete follow-up is needed to determine more definitively the long-term outcomes of this procedure," Courcoulas said. In addition, she noted that there aren't many studies on selecting who the best patients are for these surgeries, and whether or not specific procedures have better or worse results.
For more information on weight loss surgery, visit the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.