Treatment strategies for insulin-dependent diabetics with ESRD: a cost-effectiveness decision analysis model

Abstract

Clinical decision analysis has become an important tool for evaluating specific clinical scenarios and exploring public health policy issues. A decision analysis model that incorporates patient preferences regarding various outcomes, as well as cost, may be particularly informative in patients with type I diabetes and end-stage renal disease (ESRD). Such a model that includes pancreas transplantation as a treatment choice has not been performed and is presented in this study. The decision tree consisted of a choice between four possible treatment strategies: dialysis, kidney-alone transplant from a cadaver (KA-CAD) or living donor (KA-LD), and simultaneous pancreas-kidney (SPK) transplant. The analysis was based on a 5-year model, and the measures of outcome used in the model were cost and cost adjusted for quality of life. The measure of preference for quality of life was obtained using the "Standard Reference Gamble" method in 17 SPK transplant recipients who underwent transplantation between January, 1992 and June, 1996 at our center. The measures for various outcome states (mean +/- 1 SD) were dialysis-free/insulin-free = 1, dialysis-free/insulin-dependent = 0.6 (0.4 to 0.8), dialysis-dependent/insulin-free = 0.5 (0.36 to 0.64), dialysis-dependent/insulin-dependent = 0.4 (0.21 to 0.59), and death = 0. The expected 5-year costs for each of the treatment strategies in the model were dialysis, $216,068; KA-CAD transplant, $214,678; KA-LD transplant, $210,872; and SPK transplant, $241,207. The expected cost per quality-adjusted year for each of the treatment strategies in the model were dialysis, $317,746; KA-CAD transplant, $156,042; KA-LD transplant, $123,923; and SPK transplant, $102,422. SPK transplantation remained the optimal strategy after varying survival probabilities, costs, and utilities over plausible ranges by means of one-way sensitivity analysis. In conclusion, according to the 5-year cost-utility model presented in this study, SPK transplantation is the most cost-effective treatment strategy for a patient with type I diabetes and ESRD. From a policy standpoint, looking at the cost alone of pancreas transplantation is deceiving. In these patients, who may view various outcome states differently, it would be important to take into account cost adjusted for quality of life when evaluating this procedure.