BACKGROUND-: The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial assigned patients with type 2 diabetes mellitus to prompt coronary revascularization plus intensive medical therapy versus intensive medical therapy alone and reported no significant difference in mortality. Among patients selected for coronary artery bypass graft surgery, prompt coronary revascularization was associated with a significant reduction in death/myocardial infarction/stroke compared with intensive medical therapy. We hypothesized that clinical and angiographic risk stratification would affect the effectiveness of the treatments overall and within revascularization strata. METHODS AND RESULTS-: An angiographic risk score was developed from variables assessed at randomization; independent prognostic factors were myocardial jeopardy index, total number of coronary lesions, prior coronary revascularization, and left ventricular ejection fraction. The Framingham Risk Score for patients with coronary disease was used to summarize clinical risk. Cardiovascular event rates were compared by assigned treatment within high-risk and low-risk subgroups. Overall, no outcome differences between the intensive medical therapy and prompt coronary revascularization groups were seen in any risk stratum. The 5-year risk of death/myocardial infarction/stroke was 36.8% for intensive medical therapy compared with 24.8% for prompt coronary revascularization among the 381 coronary artery bypass graft surgery-selected patients in the highest angiographic risk tertile (P=0.005); this treatment effect was amplified in patients with both high angiographic and high Framingham risk (47.3% intensive medical therapy versus 27.1% prompt coronary revascularization; P=0.010; hazard ratio=2.10; P=0.009). Treatment group differences were not significant in other clinical-angiographic risk groups within the coronary artery bypass graft surgery stratum, or in any subgroups within the percutaneous coronary intervention stratum. CONCLUSION-: Among patients with diabetes mellitus and stable ischemic heart disease, a strategy of prompt coronary artery bypass graft surgery significantly reduces the rate of death/myocardial infarction MI/stroke in those with extensive coronary artery disease or impaired left ventricular function. CLINICAL TRIAL REGISTRATION-: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00006305. © 2012 American Heart Association, Inc..