V.A. Cooperative Study on antiplatelet agents in diabetic patients after amputation for gangrene: III. Definitions and review of design and baseline characteristics.

This report summarizes the major design features, methods, and baseline characteristics of patients enrolled in a Veterans Administration Cooperative Study. In eleven V.A. centers, 231 male diabetic patients who had either a recent amputation for gangrene (N = 207) or active gangrene (N = 24) were randomly assigned to a group which received aspirin (325 mg t.i.d.) plus dipyridamole (75 mg t.i.d.) (N = 110) or two placeboes t.i.d. (N = 121). Major end point were vascular death and amputation of the opposite extremity for gangrene. Forty-one percent of the 563 patients screened were enrolled during a 39 month period. Enrollment errors were found in 8.7%. Historically, the two groups were well matched regarding the following variables: age, duration of diabetes, insulin therapy, previous oral agent therapy, hypertension, myocardial infarction, congestive heart failure, renal disease, sensory neuropathy, and smoking. The drug therapy group had an increased frequency of a history of cerebrovascular disease (19% vs 7%, p = 0.01). The groups were well matched regarding amputation site, obesity, extent of lower extremity vascular disease, retinopathy, and neuropathy upon examination. Their baseline fasting values of glucose, cholesterol, triglycerides, and creatinine were also comparable. We conclude that this study should provide definitive data on the efficacy of these antiplatelet agents in preventing further vascular disease in this patient group. It should also provide new prospective data on the natural history of vascular disease, and the association of vascular risk factors with subsequent vascular events in this patient population.