Bariatric Surgery Still Tops Meds for Glycemic Control at 5 Years: STAMPEDE

Marlene Busko

April 14, 2016

CHICAGO, IL — Five-year findings of the STAMPEDE trial of 150 very overweight or obese patients with uncontrolled type 2 diabetes were consistent with interim 3-year results[1]. More patients who had gastric bypass or sleeve gastrectomy attained durable glycemic control (HbA1c <6.0%) than patients who received only intensive medical therapy.

Moreover, patients who had metabolic surgery had larger, more durable weight loss, needed fewer cardiovascular and glucose-lowering medications, and had greater improvements in cardiovascular-risk markers and quality-of-life measures. The main adverse event was mild anemia.

These metabolic outcomes were similar in patients with a body-mass index (BMI) of 27 to 34 vs those with a BMI of 35 to 43, Dr Philip R Schauer (Cleveland Clinic, OH) pointed out, presenting these findings at a clinical-research session at the American College of Cardiology 2016 Scientific Sessions. This is "important," since "most insurance companies and most guidelines do not cover bariatric surgery for BMI less than 35," he noted.

Thus, metabolic surgery "should be considered as a treatment option in this patient population" with a BMI of 27 to 43 and uncontrolled type 2 diabetes, he said. However, the findings in this small, single-center study should be confirmed, and larger, longer multicenter studies are needed to investigate cardiovascular outcomes and diabetes-related microvascular complications, he acknowledged.

Session panelist Dr Eileen M Handberg (University of Florida, Gainesville) wondered which surgery was best. Schauer replied that the trial was not powered to detect this, but "if [patients] have type 2 diabetes and are not well controlled, we generally encourage them to go with the gastric-bypass procedure."

This study "confirms the ongoing benefit of bariatric surgery," panelist Dr Allen J Taylor (MedStar Georgetown University Hospital and MedStar Washington Hospital Center, Washington, DC) told heartwire from Medscape. "What we really need to know now is health economics and . . . cardiovascular outcomes," he said.

Obese Patients With Uncontrolled Diabetes

Only half of the many patients with type 2 diabetes in the US achieve glycemic control with current medical treatment, Schauer noted.

STAMPEDE was designed to compare the safety and efficacy of the two most common types of bariatric surgery vs intensive medical therapy for treating uncontrolled type 2 diabetes. The researchers randomized patients who were 20 to 60 years old with an HbA1c >7%, and BMI 27 to 43 to receive medical therapy alone (50 patients) or Roux-en-Y gastric-bypass surgery (50) or sleeve gastrectomy (50).

The patients had a mean age of 49, a mean BMI of 36, and 66% were female. They had "fairly advanced" diabetes with an average diabetes duration of 8.5 years; about half were taking at least three antidiabetic medications, and about half were taking insulin.

All patients received lifestyle intervention and a "fairly aggressive" drug therapy that included oral agents, injectable glucagonlike peptide-1 (GLP-1) agonists, and insulin to attain an HbA1c <6%, and they had visits with an endocrinologist, a psychologist, and a dietician and frequent follow-up, Schauer explained.

A 3 years, glycemic control was better in the patients who received bariatric surgery.

5-Year Results: Persistent Glycemic Control With Fewer Meds

At 5 years, 90% of the participants remained in the study. Half of the patients in the surgery groups but only less than a quarter in the medical-therapy group met the ADA-recommended glycemic-therapy target of an HbA1c <7%. One in five patients in the surgery groups but none in the medical-therapy group had diabetes remission (HbA1c <6% without antidiabetic medications).

5-Year Glycemic-Control Outcomes

Outcome Medical therapy, n=38 (%) Gastric bypass, n=49 (%) Sleeve gastrectomy, n=47 (%) P, gastric bypass vs medical therapy P, sleeve gastrectomy vs medical therapy
HbA1c <6% 5 29 23 0.005 0.02
HbA1c <6% without diabetes meds 0 22 15 0.002 0.02
HbA1c <7% 21 51 49 0.004 0.008

The patients in the surgery groups attained this glycemic control with fewer antidiabetic medications (often none), including less use of insulin.

More patients in the sleeve-gastrectomy group (25%) and in the gastric-bypass group (45%) than in the medical-therapy group (2%) were taking no antidiabetic medications (P<0.05).

In contrast, only 12% of patients in the gastric-bypass group and 11% of patients in the sleeve-gastrectomy group vs 40% of patients in the medical-therapy group were taking insulin (P<0.05).

Patients in the surgery groups also took fewer cardiovascular medications.

No Benefits in Nephropathy, Retinopathy, No Major Harms

Patients who had undergone bariatric surgery reported better general health and less bodily pain than the other patients (P<0.05), based on replies to the RAND 36-item short-form health survey. They also had significantly improved levels of cardiovascular biomarkers (C-reactive protein, apolipoprotein A, myeloperoxidase, leptin, and plasminogen activator inhibitor-1).

There were no significant differences in albuminuria or in retinopathy, macular edema, or visual acuity between patients in the surgery groups and those in the medical group.

There were also no significant between-group difference in blood pressure or LDL cholesterol, which panelist Dr Clyde Yancy (Northwestern University, Chicago, IL) questioned. "We really endorse the importance of weight loss; certainly previous data suggest that a weight loss of 10 kg would probably result in a drop of systolic blood pressure of 8 or 10 mm Hg," he noted.

Schauer replied that the patients had well-controlled blood pressure and cholesterol levels at study entry; those who had surgery were, however, able to maintain normal levels using fewer medications.

There were no perioperative deaths related to bariatric surgery. The most common adverse event in the bariatric-surgery group was mild anemia (mean hemoglobin 12 g/dL), which occurred in 49% of patients who had sleeve gastrectomy vs 16% in the medical-therapy group (P<0.05).

The most common adverse effect in the medical-therapy group was weight gain of >5%, which occurred in 19% of patients in the medical-therapy group vs none of the patients in the surgery groups.

The STAMPEDE study was funded by Ethicon. Schauer is a paid consultant for Ethicon Endo-Surgery and the Medicines Company; he has ownership or partnership interest in GAME, SE QHC, and SurgiQuest, and he has received research grants from Ethicon Endo-Surgery and Pacira Pharmaceuticals. Yancy has no relevant financial relationships. Taylor reports receiving consultant fees/honoraria from Amgen and Eli Lilly and being on the speaker's bureau of Sanofi.

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