Costs and effectiveness of angiotensin converting enzyme inhibition in patients with congestive heart failure.

BACKGROUND Chronic heart failure is associated with a poor prognosis and reduced survival rates. The addition of vasodilator drug therapy to conventional therapy for congestive heart failure has resulted in improved survival. METHODS Adopting a societal viewpoint, we designed a decision analytic model to analyze the costs and effectiveness of three therapies available for the treatment of congestive heart failure: standard therapy (digoxin and diuretic therapy) plus (1) no vasodilator agents, (2) hydralazine hydrochloride-isosorbide dinitrate combination, and (3) enalapril. In addition, we performed sensitivity analyses to determine which model variables were influential in determining incremental cost-effectiveness ratios (cost of drug, cost of hospitalization, efficacy of agents, etc). We used data from three major randomized controlled trials to estimate treatment efficacy, mortality rates, and hospitalization rates. RESULTS An additional year of life gained by a patient receiving hydralazine-isosorbide combination therapy compared with standard therapy required an additional expense (incremental cost-effectiveness ratio) of $5600. Compared with the hydralazine-isosorbide combination therapy, the incremental cost-effectiveness ratio for enalapril therapy was $9700 per year of life saved. These results were insensitive to wide variations in our baseline assumptions. CONCLUSIONS The cost per year of life saved by vasodilator therapy is much lower than that of other accepted medical therapies. Although the cost per year of life saved for hydralazine-isosorbide combination therapy is lower than that for enalapril therapy, enalapril therapy saves more lives, and the incremental cost of enalapril therapy is justified by the added benefits.