From the Journals

Gastric bypass T2D benefit can fade over time



Adding Roux-en-Y gastric bypass surgery to lifestyle and medical management of type 2 diabetes provided significant benefits, but the effect diminished over time, according to findings published Jan. 16 in JAMA.

In a randomized study of 113 obese patients with diabetes, about 50% of those who received gastric bypass in addition to lifestyle and medical management achieved the composite endpoint of a hemoglobin A1c (HbA1c) value of less than 7%, an LDL cholesterol level of less than 100 mg/dL, and a systolic blood pressure of less than 130 mm Hg after 1 year, reported Sayeed Ikramuddin, MD, FACS, of the department of surgery at the University of Minnesota, Minneapolis, and his coauthors. For comparison, just 16% in the lifestyle/medical management group achieved the endpoint (difference, 34%; 95% confidence interval, 14%-54%; P = .003) .

At 5 years’ follow-up, about 23% of patients in the gastric bypass group and 4% in the lifestyle/medical management group achieved the composite triple endpoint (difference, 19%; 95% CI, 4%-34%; P = .01), the authors reported.

The study included 120 patients at four sites in the United States and Taiwan, 7 of whom either died or were lost to follow-up before completion of the study. Participants had an HbA1c level of 8% or higher and a body mass index between 30 and 39.9 kg/m2.

Patients were randomized to receive either 2 years of lifestyle and medical management alone or in conjunction with standardized Roux-en-Y gastric bypass. During the first 2 years of intervention, patients were told to record weight, exercise, and food intake and were prescribed 325 minutes of physical activity per week. Participants also met regularly with a trained interventionist and an endocrinologist and were given pharmacologic therapy for hyperglycemia, cholesterol, and hypertension, the authors said. Aside from usual visits with a primary physician, all study interventions ceased after the initial 2-year period.

At baseline, the group that received only lifestyle/medical management had a mean BMI of 34.4 and HbA1c level of 9.6%, compared with a mean BMI of 34.9 and HbA1c level of 9.6% in the gastric bypass group.

Primary endpoint success rates decreased in both groups between years 1 and 3, going from 50% to 23% in the gastric bypass group and from 16% to 4% in the lifestyle/medical management group, but it remained stable from year 3 through year 5, Dr. Ikramuddin and his coauthors said in the report.

Overall, 26% of patients who had gastric bypass surgery during the first year achieved the triple endpoint at 5 years, compared with 8% of those who did not have surgery (difference, 18%; 95% CI, 6%-32%; P = .04).

The mean weight loss for participants in the gastric bypass group was 21.8% at 5 years, compared with 9.6% in the lifestyle/medical management group (difference, 12.2%; 95% CI, 8.9%-15.5%).

The results suggest that “gastric bypass provides significant benefit but with a smaller and less durable effect size than what is seen in the evaluation of glycemic control alone,” the authors wrote.

“Because the effect size diminished over 5 years, further follow-up is needed to understand the durability of the improvement,” Dr. Ikramuddin and his colleagues concluded.

Dr. Ikramuddin disclosed relationships with Novo Nordisk, USGI Medical, Medica, Metamodix, Medtronic, ReShape Medical, and EnteroMedics.

SOURCE: Ikramuddin S. JAMA. 2018;319(3):266-278.

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