Six years after undergoing Roux-en-Y gastric bypass (RYGB) surgery, severely obese patients sustained significant weight loss and showed increased rates of diabetes remission and decreased cardiovascular risk factors when compared with severely obese patients who did not undergo weight loss surgery, according to the results of a study published Sept. 17 of the Journal of the American Medical Association.
"These results suggest that gastric bypass surgery is a very viable option for the severely obese patient, especially those patients who present with major cardiovascular and metabolic risk, such as diabetes," the study's lead author, Ted C. Adams, PhD, MPH, of the University of Utah in Salt Lake City, said in a video interview posted on the JAMA website.
The study followed 1,156 severely obese (body mass index [BMI] greater than 35, mean BMI 45.9) participants age 18 to 72. The study group was made up of 418 patients who received gastric bypass surgery. Control group 1 was comprised of patients who sought gastric bypass surgery but did not receive it, largely because of lack of insurance coverage, according to Adams. The investigators randomly selected 321 participants from a Utah database of severely obese people to make up control group 2.
All participants had baseline examinations at either the University of Utah Center for Clinical and Translational Science or its outpatient clinic site. Follow-up exams at the two- and six-year endpoints were conducted at the hospital, clinic site, home visits, review of medical records or by telephone. At six years, the study had data for 92.6 percent of the surgery group, 72.9 percent of control group 1 and 96.9 percent of control group 2.
The surgical patients had lost an average of 34.9 percent of body weight at the two-year marker; at the six-year marker they had regained some weight, for a net loss of 27.7 percent over the period. Also at six years, 96 percent of surgery patients had maintained more than 10 percent weight loss and 76 percent had maintained more than 20 percent weight loss. In contrast, at the six-year marker control group 1 showed a net weight gain of 0.2 percent, and there was no change in control group 2.
Among the surgical patients there was a 62 percent remission of diabetes after six years, compared with 8 percent in control group 1 and 6 percent in control group 2. Hypertension remission was 42 percent in the surgical group, 9 percent in control group 1 and 15 percent in control group 2.
"These show a very profound result in terms of the durability of weight loss long-term [among the surgical study group]," Adams said. "And a preventive benefit was shown in the significantly reduced incidence of diabetes, hypertension and hyperlipidemia among the surgical patients."
Noting that it is the longest and largest study of gastric bypass to date, Adams reported that he and his colleagues intend to follow these patients at least up to the 10-year marker.
"We are interested to determine if the improved benefits shown at two years and six years continue out to 10 years, and to what degree the modest weight gains that may occur up to 10 years may influence diabetes remission, as well as other metabolic and cardiovascular risks. We hope also that there will be continued opportunity to look at changes in heart function as well as heart geometry, and we will be looking very closely at how weight loss impacts the degree of body composition."
In an accompanying editorial, Anita P. Courcoulas, MD, MPH, of the University of Pittsburgh Medical Center, wrote that the findings are “important because they show in a RYGB cohort and control group with nearly complete follow-up at six years that weight loss and associated health benefits following RYGB are durable. The mortality rates in this study were too small to assess statistically, but serve as a reminder of an uncommon but important outcome needing objective monitoring.”
The study authors recorded 12 deaths over the six-year period in the surgical study group, of which four were attributed to suicide. Adams said that the investigators intend to further explore the psychological ramifications of gastric bypass surgery in the 10-year follow-up study.