Both weight loss and its associated improvements in cardiovascular and metabolic risk factors persisted for 6 years in most of the 418 severely obese adults who underwent Roux-en-Y gastric bypass surgery in a prospective study published in the Sept. 19 JAMA.
Despite some weight regain over time, surgery patients showed a mean weight loss of 28% at 6-year follow-up, as well as higher remission rates for diabetes, dyslipidemia, and hypertension, compared with the two control groups, said Ted D. Adams, Ph.D., of the department of internal medicine, University of Utah, Salt Lake City, and his associates.
"Considering the 5%-9% weight loss at 1 year with only 2%-6% weight loss after 4 years of intensive lifestyle-based and medication-based therapy, the weight-loss maintenance of 28% ... in our Utah study is quite significant," they noted.
The study involved severely obese adults with a body mass index of 35 kg/m2 or higher (mean BMI 45.9 kg/m2), of whom 82% were women and 96% were white. In addition to the patients who underwent either open or laparoscopic gastric bypass, there were 417 obese subjects in the first control group who were assessed for the surgery at the same time as the intervention group but did not have the surgery, and 321 obese subjects in the second control group who were randomly selected from a population-based sample of Utah residents.
Subjects in the control groups did not receive any weight-loss intervention as part of the study but were free to pursue it on their own. Over time, 101 of the subjects from both control groups chose to have bariatric surgery.
In the surgical group, mean weight loss was 35% at 2 years and 28% at 6 years, representing a 7% regain over time. By comparison, neither control group showed any significant weight loss or regain.
Diabetes remitted in 75% of the bypass group at 2 years, decreasing to 62% at 6 years. Despite the recurrence of diabetes in some patients, this long-term remission rate was dramatically better than the remission rates in the control groups (8% and 6%, respectively).
Similarly, the proportion of bypass patients who developed index diabetes during follow-up was markedly lower in the bypass group (2%) than in either control group (17% and 15%, respectively).
Remission of hypertension also was greater 6 years after bypass surgery (42%) than in the control groups (18% and 9%, respectively). Rates of high LDL cholesterol and triglycerides followed the same pattern, Dr. Adams and his colleagues wrote (JAMA 2012;308:1122-31).
Importantly, the weight loss and the concurrent improvement in cardiovascular and metabolic risk factors did not improve mortality. There were 29 deaths: 12 in the bypass group (3%); 14 in the first control group (3%); and 3 in the second control group (1%).
Notably, suicide was significantly more common in the bypass patients than in the control subjects. There were four suicides and three poisonings "of undetermined intention" overall, and six of these seven events occurred in bypass patients. The reason for this excess in the surgery group is unknown, but it is consistent with the finding that the mental component of the SF-36 fails to improve during follow-up, even though the physical component improves markedly among gastric bypass patients.
Other investigators have postulated that bariatric surgery precipitates profound changes "that may generate tension and pose special social, psychological, and lifestyle challenges. Preoperative and postoperative psychological assessment of social and emotional status related to post–bariatric surgical expectations and the potential risk of self-destructive behavior might be warranted," Dr. Adams and his associates said.
The rate of perioperative complications was 3% in the surgery group, and there were 38 hospitalizations for bypass-related indications.
This study was supported by the National Institutes of Health, the National Institute of Diabetes and Digestive and Kidney Diseases, and the National Center for Research Resources. Dr. Adams’s associates reported ties to Vivus, Orexigen, GlaxoSmithKline, Health Outcome Solutions, and Ethicon Endo-Surgery.