Effects of aggressive cholesterol lowering and low-dose anticoagulation on clinical and angiographic outcomes in patients with diabetes: the Post Coronary Artery Bypass Graft Trial.
Diabetic patients have greater risk for coronary heart disease (CHD) events after coronary artery bypass graft (CABG) surgery than nondiabetic patients. The Post CABG trial studied the effects of aggressive cholesterol lowering and low-dose anticoagulation in diabetic patients compared with nondiabetic patients. A double-blind, randomized clinical trial in 1,351 patients (1-11 years after CABG), the Post CABG trial consisted of two interventions (aggressive cholesterol-lowering versus moderate lowering and low-dose warfarin versus placebo) on angiographic end points. Angiographic changes in saphenous vein graft conduits 4.3 years after entry were compared in 116 diabetic and 1,235 nondiabetic patients. Seven clinical centers participated in the trial, as well as the National Institutes of Health project office (National Heart, Lung, and Blood Institute), the coordinating center (Maryland Medical Research Institute), and the Angiogram Reading Center (University of Minnesota). Baseline characteristics of the diabetic patients differed from the nondiabetic patients in the following ways: percentage of women participants, 15 vs. 7%, P = 0.002; mean baseline weight, 87.4 vs. 82.8 kg, P = 0.006; mean BMI, 29.5 vs. 27.6 kg/m2, P = 0.0002; mean systolic blood pressure, 141.7 vs. 133.6, P < 0.0001; mean triglyceride concentrations, 2.09 vs. 1.77 mmol/l, P < 0.0001; and mean HDL cholesterol concentrations, 0.93 vs. 1.02 mmol, P = 0.0001. The percentage of clinical events was higher in diabetic than nondiabetic patients (20.6 vs. 13.4, P = 0.033) and angiographic outcomes were not different. The benefits of aggressive cholesterol lowering were comparable in diabetic and nondiabetic patients for the angiographic end points. Warfarin use was not associated with clinical or angiographic benefit. Diabetic patients in the Post CABG trial had more CHD risk factors at study entry and higher clinical event rates during the study than nondiabetic patients. The benefits of aggressive cholesterol lowering in diabetic patients were comparable to those in nondiabetic patients for both angiographic and clinical end points. The small number of diabetic patients provided limited power to detect significant differences between diabetic and nondiabetic patients or between diabetic patients in the aggressive versus moderate cholesterol treatment strategies.