No advantage to distal vs standard gastric bypass in severe obesity

Last Updated: 2016-09-21

By Marilynn Larkin

NEW YORK (Reuters Health) - For patients with an extremely high BMI, distal Roux-en-Y gastric bypass is no more effective than the standard procedure, and is associated with serious adverse effects, researchers in Norway report.

"Up to one-third of patients undergoing bariatric surgery have a body mass index (BMI) of more than 50. Following standard gastric bypass, many of these patients still have a BMI greater than 40 after peak weight loss," write Dr. Hilde Risstad of Oslo University Hospital and colleagues.

To see if distal gastric bypass might yield better results, the team compared the two procedures in patients with a BMI of 50 to 60.

As reported in JAMA Surgery, online September 14, the study included 57 patients who were randomly assigned to undergo standard gastric bypass and 56 who underwent distal gastric bypass and were followed for two years.

BMI was reduced by an average 17.8 after standard gastric bypass and 17.2 after the distal approach (mean between-group difference: 0.6).

Distal bypass resulted in great reductions in total cholesterol and low-density lipoprotein cholesterol compared with standard bypass, with between-group differences of 19 mg/dL and 28 mg/dL, respectively. Distal bypass also resulted in greater reductions in fasting glucose levels and hemoglobin A1c. However, secondary hyperparathyroidism and loose stools were more frequent after distal bypass.

Although the number of adverse events and changes in quality of life did not differ between the groups, the authors highlight that one patient developed liver failure and two patients developed protein-calorie malnutrition following distal gastric bypass.

Writing on behalf of her colleagues, Dr. Risstad told Reuters Health by email, "We were surprised to find no difference in weight loss outcome between the two groups, as most of the existing research has shown increased weight loss after distal gastric bypass."

"Despite similar weight loss, blood tests indicated more malabsorption in patients with distal gastric bypass and a few patients developed serious adverse effects related to malabsorption," she added.

Dr. Risstad concluded, "We therefore recommend the use of standard gastric bypass over this variant of distal gastric bypass for patients with severe obesity."

In an editorial, Dr. Oliver Varban and Dr. Justin Dimick, both of the University of Michigan, Ann Arbor say distal gastric bypass "should be abandoned."

Dr. Philip Schauer, director of the Bariatric and Metabolic Institute at Cleveland Clinic, commented, "The study is a well done randomized controlled trial . . . It's important to note that this type of distal gastric bypass does not significantly reduce bowel absorption length but only diverts bile and pancreatic enzymes to the distal small bowel. Therefore, no improvement in weight loss is not too surprising."

"There were, however, some significant metabolic benefits in terms of reducing hemoglobin A1c and cholesterol," Dr. Schauer told Reuters Health by email. "But, those advantages seem to be offset with an increase in nutritional deficiencies, and one case of liver failure with the distal bypass."

He, too, concluded, "This version of this distal bypass therefore provides no significant advantages over a standard bypass for high-BMI patients in general."

SOURCE: http://bit.ly/2cVijRH and http://bit.ly/2cVhOXS

JAMA Surg 2016.