Objective: Current guidelines recommend treating patients with type 1 diabetes mellitus with ACE inhibitors after the onset of microalbuminuria. Recent clinical trials have shown ACE inhibitors can affect the development of nephropathy when initiated prior to the onset of microalbuminuria. Our objective is to examine the cost effectiveness of treating adults aged over 20 years with an ACE inhibitor (captopril) immediately following diagnosis of type 1 diabetes versus treating them after the onset of microalbuminuria.
Design: Using a semi-Markov model, we calculated four main outcome measures: lifetime direct medical costs (discounted), QALYs, cumulative incidence of end-stage renal disease (ESRD), and number of days of ESRD over a lifetime. Medical costs are in 1999 US dollars.
Setting: All analyses were from the viewpoint of a single US payer responsible for all direct medical costs, including screening for microalbuminuria, ACE inhibitor treatment (captopril), management of major diabetic complications, and routine annual medical costs not specific to diabetes.
Methods: We applied the model to a hypothetical cohort of 10,000 persons newly diagnosed with type 1 diabetes. Distribution of sex and race/ethnicity within the cohort is representative of the general US population.
Results: We estimated that the incremental cost of early use of captopril for the average adult with type 1 diabetes is USD 27,143 per QALY. This level varies considerably with age and glycaemic level. When the age at onset of diabetes is 20 years and glycosylated haemoglobin (HbA(1c)) level is 9%, the cost-effectiveness ratio is USD 13,814 per QALY. When the age at onset is 25 years and HbA(1c) level is 7%, the cost-effectiveness ratio is USD 39,530 per QALY.
Conclusion: This model, with its underlying assumptions and data, suggests that early treatment with captopril provides modest benefit at reasonable cost effectiveness, from the US single-payer perspective, in the prevention of ESRD compared with delaying treatment until diagnosis of microalbuminuria. Early treatment with other ACE inhibitors will provide similar cost effectiveness if they have equivalent efficacy, compliance and price per dose. Treatment may be considered among patients at age 20 years with new onset of type 1 diabetes. This conclusion is sensitive to the extent that ACE inhibitors delay onset of microalbuminuria. Other factors such as the patient's age and glycaemic level must be considered when deciding to initiate early treatment.