Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI2D)

BACKGROUND:

Type 2 diabetes mellitus, which is becoming more prevalent in our society as the population ages, is one of the strongest risk factors for coronary artery disease (CAD) and consequent mortality. In addition to generating an enormous toll in human suffering, diabetes places an economic burden approaching 100 billion dollars annually on the U.S. health care system. Despite the well known dismal prognosis of diabetes complicated by angiographically documented CAD, the optimal treatment paradigm for this large group of patients has not been studied. Coronary revascularization, while increasingly used, has not been directly shown to be of additional benefit to simultaneous intensive medical management of CAD along with management of hyperglycemia, hypertension, dyslipidemia, and other risk factors. Moreover, while intensive efforts to lower HbA1c have been demonstrated to favorably affect the clinical course of Type 2 diabetes mellitus in terms of microvascular complications, the optimal hyperglycemia management strategy with regard to macrovascular outcome is not known.

These critical treatment dilemmas have motivated the development of BARI 2D, a multicenter randomized trial designed to determine in patients with Type 2 diabetes and stable CAD: 1) the efficacy of initial elective coronary revascularization combined with aggressive medical therapy, compared to an initial strategy of aggressive medical therapy alone; and 2) the efficacy of a strategy of providing more insulin (endogenous or exogenous), versus a strategy of increasing sensitivity to insulin (reducing insulin resistance), in the management of hyperglycemia, with a target HbA1c level of less than 7.0% for each strategy.

DESIGN NARRATIVE:

The BARI 2D trial is a multicenter study that uses a 2x2 factorial design, with 2400 patients being assigned at random to initial elective revascularization with aggressive medical therapy or aggressive medical therapy alone with equal probability, and simultaneously being assigned at random to an insulin providing or insulin sensitizing strategy of glycemic control (with a target value for HbA1c of less than 7.0% for all patients). Following confirmation of patient eligibility and provision of written consent, patients were randomized as shown below:

Number of Patients Per Treatment Assignment (N=2400 patients in total)

Stable Ischemic Heart Disease Treatment Strategy and Glycemic Control Strategy:

Revascularization and Insulin Providing (IP) N=600; Revascularization and Insulin Sensitizing (IS) N=600; Medical and Insulin Providing (IP) N=600; Medical and and Insulin Sensitizing (IS) N=600.