An economic analysis of captopril in the treatment of diabetic nephropathy

OBJECTIVE - The results of a recent clinical trial, The Effect of ACE inhibition on Diabetic Nephropathy, demonstrated that captopril reduced the rate of renal failure, end-stage renal disease (ESRD), and death in patients with IDDM and nephropathy. The purpose of this study was to determine the cost-benefit and cost-effectiveness of captopril as a therapy in patients with IDDM as well as the potential savings for all patients with diabetes and nephropathy. RESEARCH DESIGN AND METHODS - We used the results from a randomized, placebo-controlled trial comparing captopril (207 patients) with placebo (202 patients), whose purpose was to determine whether captopril has kidney-protecting properties independent of its effect on blood pressure in diabetic nephropathy to develop a model of medical treatment for patients before progression to ESRD. To model the course of illness after progression to ESRD and to extend the model to patients with NIDDM, we used data from the U.S. Renal Data System and published literature. Medical resource cost data were based predominantly upon Medicare reimbursement levels, published wholesale drug prices, and surveying health care providers. The economic model uses a payer perspective to estimate direct cost. The cost to society (indirect cost) associated with lost patient productivity due to ESRD was also estimated. Using this information, we predicted the costs incurred annually and over a lifetime if patients with IDDM and NIDDM and overt nephropathy were treated with either placebo or captopril. We also constructed a model of the overall prevalence of diabetic nephropathy to estimate the aggregate savings in total U.S. health care expenditures. RESULTS - Treatment with captopril resulted in an absolute direct cost savings or benefit of $32,550 per patient with IDDM over the course of a lifetime compared to treatment with placebo. For patients with NIDDM, the direct cost savings totaled $9,900 per patient. Absolute savings were found for indirect costs as well: $84,390 per patient with IDDM and $45,730 per patient with NIDDM. If captopril therapy were initiated in 1995 for patients with either IDDM or NIDDM and nephropathy, the aggregate health care cost savings (i.e., direct cost savings alone) mould be $189 million a year for the year 1999 and $475 million a year in 2004; the present value of cumulative health care cost savings for these 10 years would be $2.4 billion. CONCLUSIONS - The use of captopril in diabetic nephropathy will provide significant savings in health care costs; in addition, it will result in savings in indirect cost, which reflects the broader societal benefit.