Gastric Bypass Has Advantages in Less Obese Patients
June 16, 2011 — There are benefits to performing laparoscopic Roux en Y gastric bypass (RYGB) in obese patients who have a body mass index (BMI) below 35 kg/m2, according to a study reported at the American Society for Metabolic and Bariatric Surgery 28th Annual Meeting in Orlando, Florida.
Among patients who underwent the surgery, the rates of remission of type 2 diabetes were higher in those with a BMI below 35 kg/m2 than in those with higher BMIs. The “less obese” patients also lost a greater percentage of their excess weight in the first year after surgery than their peers with higher BMIs.
“The study raises the question of whether early referral leads to better outcomes,” John Morton, MD, director of bariatric surgery at Stanford Hospital & Clinics at Stanford University in Palo Alto, California, and an investigator with the study, noted in a conference statement.
“Bariatric surgery is tremendous for weight loss, but its other big advantage is improving medical problems, in particular type 2 diabetes,” Dr. Morton noted in an interview with Medscape Medical News.
Outcomes Better at Lower BMI
Dr. John Morton
Current guidelines from the National Institutes of Health recommend that gastric bypass be reserved for patients who have a BMI of 35 kg/m2 or higher and an obesity-related condition, or who have a BMI of at least 40 kg/m2.
Dr. Morton’s team took a look back at 980 patients who underwent laparoscopic RYGB at their institution between 2004 and 2010. “We ask patients to lose some weight before surgery because it’s a good way to make sure they are committed to the program, and it makes the surgery a little bit safer,” Dr. Morton said. “Therefore, we had some patients below a BMI of 35 kg/m2 at the time of surgery.”
For the analysis, the patients were grouped according to their presurgery BMI: below 35 kg/m2, 35 to 39.9 kg/m2, 40 to 49.9 kg/m2, and above 50 kg/m2.
“When we examined type 2 diabetes resolution rates, we found that those with the lowest BMI had the best resolution rates,” Dr. Morton reported. All 12 patients with a BMI below 35 kg/m2 no longer had type 2 diabetes after surgery, whereas patients with higher BMIs had remission rates of roughly 75%.
“We are looking to entertain the idea that maybe obese patients should have the option of surgical intervention for their diabetes sooner rather than later because, as the study showed, as the BMI gradient goes up, your diabetes resolution rate with surgery goes down,” Dr. Morton said.
The researchers also found that patients with a BMI below 35 kg/m2 who had the surgery had lost more of their excess weight at 3, 6, and 12 months than patients with a higher BMI.
After 1 year, the patients with BMIs below 35 kg/m2 had lost 167% of their excess weight. By comparison, those with a BMI from 35 to 39.9 kg/m2 had lost 112%, those with a BMI from 40 to 49.9 kg/m2 had lost 85%, and those with a BMI above 50 kg/m2 had lost 67% of their excess weight.
Laparoscopic RYGB also took less time in patients with the lowest BMI (170 minutes) than in those with higher BMIs (177 minutes, 182 minutes, and 194 minutes, respectively).
Reevaluation of BMI Guideline Needed
In an interview with Medscape Medical News, John David Scott, MD, a bariatric surgeon at Greenville Hospital System University Medical Center in South Carolina, who was not involved in the study, said that “the BMI level of 35 is an arbitrary standard set many years ago that certainly needs to be reevaluated.”
“Most of the evidence that has been coming out lately has shown not only a positive weight loss benefit for that particular group, but also positive overall health effects,” he added. “In particular, the resolution of diabetes is astounding. To be able to offer patients a surgical cure for their type 2 diabetes is very exciting,” Dr. Scott said.
Dr. Morgan has disclosed no relevant financial relationships. Dr. Scott reports receiving speaker fees from WL Gore & Associates and fellowship support from Ethicon Endo Surgery.
American Society for Metabolic and Bariatric Surgery (ASMBS) 28th Annual Meeting: Abstract P-54. Presented June 16, 2011.