Gastric bypass benefits persist over long-term follow-up, study finds

Roux-en-Y gastric bypass had benefit for weight loss and other positive health outcomes over the long term, according to a new study.

Researchers performed a long-term observational prospective study of Roux-en-Y gastric bypass involving three groups of patients with severe obesity: those who sought and received surgery, those who sought but did not receive surgery, and those who did not seek or receive surgery. Clinical exams were performed at baseline and at two years, six years, and 12 years for type 2 diabetes, hypertension, and dyslipidemia.

Type 2 diabetes was defined as a fasting blood glucose level of 126 mg/dL (7 mmol/L) or higher, an HbA1c of 6.5% or higher, or current use of antidiabetic medication. Hypertension was defined as blood pressure of at least 140/90 mm Hg while seated, current use of antihypertensive medication, or both. Dyslipidemia was defined as a fasting LDL cholesterol level of 160 mg/dL (4.14 mmol/L) or higher, an HDL cholesterol level below 40 mg/dL (1.30 mmol/L), a triglyceride level of 200 mg/dL (2.26 mmol/L) or higher, or current use of lipid-lowering medication.

Primary end points for the study were percentage of original weight lost and rates of incidence and remission for type 2 diabetes, hypertension, and dyslipidemia in surviving patients at 12 years. Study results were published Sept. 21 by the New England Journal of Medicine.

Four hundred eighteen patients in the surgery group, 417 patients in the first nonsurgery group, and 321 patients in the second nonsurgery group were included in the study. One hundred forty-seven of 417 patients in the first nonsurgery group (35%) and 39 of 321 patients in the second nonsurgery group (12%) had bariatric surgery during the 12-year follow-up period. When patients who died were excluded, clinical follow-up data were collected at 12 years for 388 of 392 patients in the surgery group (99%), 364 of 378 patients in the first nonsurgery group (96%), and 301 of 303 patients in the second nonsurgery group (99%).

Adjusted mean change in body weight from baseline was −45.0 kg, −36.3 kg, and −35.0 kg at two, six, and 12 years, respectively, in the surgery group. In the first and second nonsurgery groups, the mean change at 12 years was −2.9 kg and 0 kg, respectively. For incidence of type 2 diabetes at 12 years, the adjusted odds ratio was 0.08 for the surgery group compared with the first nonsurgery group and 0.09 compared with the second nonsurgery group (P<0.001 for both comparisons). Among the patients in the surgery group who had type 2 diabetes at baseline, diabetes was in remission in 66 of 88 patients (75%) at two years, in 54 of 87 patients (62%) at six years, and in 43 of 84 patients (51%) at 12 years. For remission of type 2 diabetes, the adjusted odds ratio was 8.9 for the surgery group compared with the first nonsurgery group and 14.8 for the surgery group versus the second nonsurgery group (P<0.001 for both comparisons). The remission rate for hypertension was significantly higher in the surgery group than in the first nonsurgery group but not in the second nonsurgery group. In addition, remission rates for dyslipidemia variables were significantly higher in the surgery group than in either of the nonsurgery groups.

The authors concluded that their study shows long-term durability of weight loss after bariatric surgery with Roux-en-Y gastric bypass, as well as related improvements in type 2 diabetes, hypertension, and lipid levels. They stated that diabetes remission rates in their study were higher than those seen in the previously conducted Swedish Obese Subjects (SOS) study, which had a 13.4-year follow-up, and speculated that the difference may be due to the fact that the current study used only the Roux-en-Y gastric bypass while the SOS study primarily used vertical banded gastroplasty. They also noted that seven patients in their study committed suicide, all after undergoing gastric bypass, and cited a “pressing, unmet need to better predict and prevent this uncommon but very serious sequela of bariatric surgery.”