Modelling and costing the consequences of using an ACE inhibitor to slow the progression of renal failure in type I diabetic patients

Antihypertensive drugs slow the progressive decline in renal function seenin patients with insulin-dependent diabetes and nephropathy. In a recentstudy, the ACE inhibitor captopril protected against this deterioration inrenal function. We developed an economic model to analyse the cost impactof ACE inhibitor treatment on progression to endstage renal failure (ESRF)in diabetic patients over 4 years. Two scenarios were compared: onedescribing the progression of a cohort of 1000 patients receiving 25 mgcaptopril three times daily, and the other for an equivalent cohort withoutsuch prophylactic treatment. Previously published data were used toestimate the transition rates for each stage from the onset of renalfailure until death. All direct costs were discounted by an annual rate of6%, and were subjected to sensitivity analysis. The discounted cost savingof ACE inhibitor treatment for a cohort of 1000 patients was estimated as0.95 million pounds over 4 years. Under sensitivity analysis, these resultswere very robust to variations in the costs of ESRF treatment. Prophylactictreatment with ACE inhibitors was predicted to provide substantialincreases in life expectancy and reduction in the incidence of ESRF, whilealso providing significant economic savings.