Tuesday, Feb. 22, 2011 – Surgical reconstruction of the stomach with Roux-en-Y bypass is more effective for bringing type 2 diabetes into remission within one year than other weight loss surgery — including gastric band procedures.
A pair-matched cohort analysis by researchers at the University of California San Francisco showed a significant advantage for bypass surgery, with resolution or improvement of diabetes in 76 percent of patients compared with 50 percent for gastric banding.
Another study, a randomized trial conducted in Taiwan, found that diabetes remission was nearly universal after one year in patients receiving a different form of bypass surgery, whereas only half of those receiving sleeve gastrectomy had resolution of diabetes (93 percent versus 47 percent).
Both studies were published in the February issue of Archives of Surgery.
“Because [bypass surgery] achieves greater weight loss, increased resolution of diabetes, and better improvement in quality of life, we conclude that, in the setting we studied, Roux-en-Y gastric bypass has a better risk-benefit profile than laparoscopic banding,” wrote the UCSF researchers, led by Dr. Guilherme Campos, who has since relocated to the University of Wisconsin.
“This information should be provided when discussing bariatric surgical options with patients,” the authors added.
But other researchers urged caution in interpreting the findings.
Dr. Mitchell Roslin, a bariatric surgeon at Lenox Hill Hospital in New York City, told MedPage Today and ABC News in an e-mail that one year was not really enough follow-up to determine superiority of one procedure over the other.
“My concern is that it [gastric bypass] is not a great operation for maintaining the weight loss,” he said.
“We have recently shown that patients experience a return in intermeal hunger, still eating less at a meal, but becoming hungry one to two hours after eating. As a result, we are seeing many patients five to 10 years from surgery who have regained 50% or more of the weight they have lost,”
Roslin said, adding that some of their previous obesity-related medical problems had returned as well.
Similarly, Dr. Scott Belsley, of St. Luke’s-Roosevelt Hospital in New York City, commented that one-year weight loss was already known to be greater with bypass surgery than lap-banding.
“If their five-year follow-up demonstrates true superiority of gastric bypass then this paper might help change clinical practice,” he wrote in an e-mail.
Campos and colleagues compared one-year outcomes in 92 morbidly obese patients (mean baseline BMI of 46) undergoing gastric bypass and a pair-matched group of 93 patients who received lap-band procedures.
This was not a randomized trial — patients selected which treatment they would receive in consultation with their physicians.
Resolution of diabetes was defined as achievement of glycemic control without medications; diabetes was considered to be improved if medication doses were reduced by more than 50 percent.
Campos and colleagues did not report numbers of resolutions and improvements separately, perhaps because only 34 patients in each group were diabetic at baseline.
Weight loss at one year was significantly greater in the bypass group, which lost an average of 64 percent of their baseline excess weight compared with 36 percent of excess weight lost in the lap-band group.
Mean BMI at follow-up was 30 in the bypass patients (range 21 to 43) and 36 in participants receiving the lap-banding (range 25 to 52).
Quality of life was not assessed at baseline, but the one-year evaluation suggested a significant advantage for the gastric bypass procedure. Bariatric Analysis and Reporting Outcome System scores for quality of life averaged 5.7 with bypass surgery versus 3.6 in the lap-band patients, Campos and colleagues reported.
Of the five domains in the Moorehead-Ardelt Quality of Life Questionnaire II, all showed higher values for the gastric bypass group, but for only one — social function — was the difference clearly significant (0.30 versus 0.18 points).
Overall complication rates were similar with the two treatments. Bypass patients had more problems requiring medical attention during the first 30 days after the procedure (11 versus two), but later revision surgery was more common with the lap-bands (12 patients versus two).
In a commentary published in the same issue of the journal, Dr. Harry C. Sax, currently at Cedars Sinai Medical Center in Los Angeles, wrote that the findings were not surprising.
He noted, though, that only about one-third of patients in both groups were diabetic and just a handful took daily insulin. He also echoed the point made by Roslin that longer-term follow-up could shed more light on the relative value of the two procedures.
“Weight loss with laparoscopic banding can approach that of Roux-en-Y gastric bypass at three years,” Sax wrote.
The Taiwanese trial, meanwhile, was remarkable because it was designed to evaluate bariatric procedures expressly as treatments for diabetes rather than for weight loss. Its 60 patients ranged from normal weight to moderately obese (BMI 25 to 34, mean 30.3).
In this study, the researchers, led by Lee-Ming Chung, MD, of National Taiwan University in Taoyuan City, chose sleeve gastrectomy as the comparator.
The bypass surgery they performed was not a strict Roux-en-Y procedure. Instead, it also included a duodenum exclusion. Sleeve gastrectomy is a simple restriction procedure that limits the amount of food patients can eat, with no duodenal exclusion.
Chung and colleagues viewed the trial as a test of the so-called foregut hypothesis of type 2 diabetes remission following bypass surgery, which holds that eliminating passage of food nutrients through the duodenum and jejunum alters metabolic signaling to normalize blood glucose levels.
The study findings supported the hypothesis, as twice as many patients undergoing the bypass surgery achieved diabetes remission — defined as fasting blood glucose of less than 126 mg/dL and glycated hemoglobin (HbA1c) of less than 6.5 percent without use of insulin or oral antihyperglycemic drugs. Mean HbA1c at baseline was about 10 percent in both groups, declining to 5.7 percent with bypass and 7.2 percent with sleeve gastrectomy.
Bypass surgery also led to greater rates of “successful diabetes treatment,” which Chung and colleagues defined as HbA1c of less than 7 percent plus normalization of low-density lipoprotein cholesterol and triglycerides.
Treatment success was observed in 57 percent of patients undergoing the bypass procedure compared with no patients in the sleeve gastrectomy group, Chung and colleagues reported.
No serious complications occurred with either procedure, the researchers indicated. Weight loss was seen in both groups, which was slightly greater in the bypass patients (final mean BMI 24.4 versus 22.8, P=0.009).
Both weight loss and declines in HbA1c values relative to baseline were apparent in both groups one month after the procedures.
The study by Campos and colleagues was supported by the National Center for Research Resources. The Taiwan study had no external funding.