A cost-effectiveness analysis of enalapril maleate in the management of congestive heart failure in Australia

Background: This study is motivated by the results of the SOLVD treatment trial (N Engl J Med 1991; 325: 293-302) which demonstrated the clinical efficacy of enalapril in the treatment of congestive heart failure but did not undertake an economic evaluation of enalapril therapy. Aims: To undertake a cost-effectiveness analysis of enalapril maleate versus placebo, in conjunction with conventional treatment, in the management of congestive heart failure in Australia. Methods: The published results from the SOLVD treatment trial are used to estimate the increase in survival, and the reduction in the number of hospitalisations, arising from the use of enalapril in the management of congestive heart failure. The costs of enalapril therapy are estimated using Australian data on the drug and non-drug costs of enalapril therapy and the costs of hospitalisation. Results: Enalapril therapy increases mean survival in heart failure patients by 1.68 to 1.80 months. The average additional drug and non-drug cost of enalapril therapy is estimated to be $1890 over a four year period, against which must be offset cost savings from a reduction in hospitalisations of $2060 to $2140. On balance, therefore, enalapril is cost saving, reducing health care costs for a congestive heart failure patient on average by $170 to $250 over a four year period. This value is sensitive to estimates of cost offsets and of improved survival which can result in either a net cost saving with enalapril of approximately $1200 per patient or a net additional cost of up to $3000 per patient (over four years) or greater than $20,000 per life-year saved. Conclusions: The addition of enalapril to conventional management of congestive heart failure in Australia should improve survival and may provide a net reduction in treatment costs compared with conventional management alone.