Beta Cell Restoration Through Fat Mitigation (BetaFat)

General Description

Obesity is one of the key risk factors in the development of type 2 diabetes. Research has shown that excess body mass is linked to insulin resistance and loss of beta-cell function, which are precursors of type 2 diabetes. Clinical studies indicate medication and weight loss attained through lifestyle changes are both effective at slowing the progression of the disease by mitigating the effects of obesity on beta-cell function. The Beta Cell Restoration Through Fat Mitigation (BetaFat) Study was created to determine if weight loss through gastric banding surgery would be more effective than metformin medication at sustaining or improving beta-cell function in individuals with prediabetes or early type 2 diabetes, who are also mildly to moderately obese.

BetaFat, a component of the Restoring Insulin Secretion (RISE) Consortium, was a two-arm, unblinded clinical trial. Study participants were recruited at the University of Southern California and randomized into two intervention groups. One group received gastric banding surgery and the other group was treated with metformin. Patients underwent assessments at baseline and at predetermined intervals during the 24-month study period. Beta-cell function, insulin sensitivity, and blood glucose levels were regularly evaluated during the study period. Participants were also monitored for adverse effects to the interventions.

Objectives

The aim of the BetaFat study was to determine whether gastric banding would be better than metformin at maintaining or restoring beta-cell function in mildly to moderately obese individuals with prediabetes or recently diagnosed type 2 diabetes.

Outcome Measure

Primary Outcome Measure:
Study participants were assessed for change in steady-state beta-cell compensation for insulin resistance from baseline to 24 months. The results were compared between the treatment groups.

Secondary Outcome Measure:
Participants were also evaluated for change in blood glucose levels during the study period.

Criteria

Inclusion Criteria:
Study participants were age 22 – 65 years; had prediabetes or diabetes for less than one year and did not receive any glucose-lowering medication, except during pregnancy; body mass index 30 – 40 kg/m2; participated in a diet, exercise, and lifestyle intervention program for at least two months within two years prior to screening; and met the glucose and HbA1c requirements.

Exclusion Criteria:
Individuals were excluded from participation if they were anemic or had known coagulopathy; had contraindications to gastric binding and MRI; excessive alcohol consumption; thyroid disease that was not sufficiently treated; cardiovascular disease; serum AST more than three times the upper limit of normal; renal disease or serum potassium abnormality; active infection; or an underlying disease or condition that would affect glucose metabolism, limit life span, increase the risk of intervention, prevent or limit study participation, or interfere with study procedures and/or outcomes.

Outcome

Study outcomes show that metformin and gastric banding had comparable effects in improving insulin sensitivity in patients with prediabetes or recently diagnosed type 2 diabetes. Both treatment groups exhibited some improvements in beta-cell function and glycemia during the study period. Also, those in the gastric banding group lost more weight and experienced faster weight loss than the patients in the metformin group. Although both treatment groups had similar results with reducing the progression of type 2 diabetes over the two-year study period, additional studies are needed to determine the long-term benefits of gastric banding versus metformin treatment.