The cost effectiveness of ACE inhibitors as first-line antihypertensive therapy

Background: Current hypertension guidelines differ in their recommendations for first-line antihypertensive therapy. Objective: To evaluate the cost effectiveness of ACE inhibitor therapy as antihypertensive first-line therapy as compared with conventional antihypertensive therapy with beta-adrenoceptor antagonists or diuretics. Study design: Cost-effectiveness analysis based on data from randomised trials and observational studies comparing the effectiveness of ACE inhibitor and conventional antihypertensive therapy, we constructed a Markov model to compare four strategies in the management of uncomplicated hypertension: (i) prescribing ACE inhibitor therapy to all patients; (ii) prescribing conventional therapy to all patients; (iii) individualised antihypertensive therapy based on the presence or absence of left ventricular hypertrophy on electrocardiography (ECG); or (iv) individualised antihypertensive therapy based on the presence or absence of left ventricular hypertrophy on echocardiography. Methods: Cost data were derived from the medical literature and focus groups, and utility values were derived from patients on antihypertensive monotherapy. All costs were calculated in 1999 Canadian dollars, but are reported in US dollars according to the 1999 purchasing power parity rate for medical and healthcare. The effectiveness of ACE inhibitor therapy in the presence of left ventricular hypertrophy was derived from observational studies. The time horizon was over a lifetime. Perspective: Third-party payer. Patients/participants: A cohort of men aged 40 years without cardiovascular comorbidity requiring antihypertensive drug therapy. Main outcome measures and results: In the baseline analysis, all four strategies resulted in expected discounted QALYs that differed from each other only at the third decimal point (i.e. less than 0.003). Given the uncertainties in the variable estimates and the small size of the differences, these differences are extremely small and unlikely to represent real differences. Even accepting the small gains as real, the resulting cost-effectiveness ratios are unattractively high: $US200 000 per QALY gained for the echocardiography strategy (compared with ECG), and $US700 000 for the 'ACE inhibitor for all' strategy (compared with ECG). The incremental cost effectiveness of prescribing ACE inhibitor therapy to everybody was never less than $US 100 000/QALY in the sensitivity analysis. Conclusions: Prescribing ACE inhibitors as antihypertensive first-line therapy in patients without cardiovascular morbidity cannot be recommended at the present time unless the aquisition costs of ACE inhibitors become substantially more attractive.