THE VETERANS-AFFAIRS IMPLANTABLE INSULIN PUMP STUDY - EFFECT ON CARDIOVASCULAR RISK-FACTORS

OBJECTIVE - To determine whether implantable insulin pump (IIP) and mu ltiple-dose insulin (MDI) therapy have different effects on cardiovasc ular risk factors in insulin-requiring patients with type 2 diabetes. RESEARCH DESIGN AND METHODS - A randomized clinical trial was conducte d at seven Veterans Affairs medical centers in 121 male patients with type 2 diabetes between the ages of 40 and 69 years receiving at least one injection of insulin per day and with HbA(1c) levels of greater t han or equal to 8% at baseline. Weights, blood pressures, insulin use, and glucose monitoring data were obtained at each visit. Lipid levels were obtained at 0, 4, 8, and 12 months, and free and total insulin l evels were obtained at 0, 6, and 12 months. All medications being take n were recorded at each visit. RESULTS - No difference in absolute blo od pressure, neither systolic nor diastolic, was seen between patients receiving MDI or IIP therapy but significantly more MDI patients requ ired antihypertensive medications. When blood pressure was modeled aga inst weight and time, IIP therapy was significantly better than MDI th erapy for systolic blood pressure in patients with BMI <33 and for dia stolic blood pressure in patients with BMI >34 kg/m(2). Total choleste rol levels decreased in the overall sample, but IIP patients exhibited significantly higher levels than MDI patients. Triglyceride levels in creased over time for both groups, with IIP patients having significan tly higher levels than patients in the MDI group. BMI was a significan t predictor of, and inversely proportional to, HDL cholesterol level. No difference in lipid-lowering drug therapy was seen between the two groups. Free insulin and insulin antibodies tended to decrease in the IIP group as compared with the MDI group. C-peptide levels decreased i n both groups. CONCLUSIONS - IIP therapy in insulin-requiring patients with type 2 diabetes has advantages over MDI therapy in decreasing th e requirement for antihypertensive therapy and for decreasing total an d free insulin and insulin antibodies. Both therapies reduce total cho lesterol and C-peptide levels.