Cost-Minimization and the Number Needed to Treat in Uncomplicated Hypertension

Abstract

The goal of this study was to compare the direct costs associated with the prescription of thiazide diuretics, β-receptor blockers (β-blockers), angiotensin converting enzyme inhibitors (ACEI), α-receptor blockers (α-blockers), and calcium channel blockers (CCB) for the prevention of stroke, myocardial infarction (MI) and premature death in uncomplicated hypertension. We performed a cost-minimization analysis based on numbers-needed-to-treat (NNT) derived from the metaanalysis of 15 major clinical trials of hypertension treatment, and the average wholesale prices of both the most commonly prescribed and the least expensive drugs in each class. The inclusion criteria for clinical trials were that they be randomized, controlled trials of drug therapy of uncomplicated mild-to-moderate hypertension with stroke, MI, or death as endpoints. The wholesale drug costs and the total direct outpatient treatment costs to prevent a stroke, MI or death among middle-aged and elderly hypertensives were our outcome measures. The estimated wholesale drug acquisition cost to prevent one major event (MI or stroke or death) ranged from $4730 to $346,236 among middle-aged patients, and from $1595 to $116,754 in the elderly; generic diuretic or β-blocker therapy was more economical than treatment with an ACEI, α-blocker, or CCB. The associated 5-year NNT was 86 for middle-aged patients and 29 for elderly patients. Diuretic therapy remained more cost-effective even under the unlikely assumption that the newer drugs were 50% more effective than diuretics at preventing these major events. The costs associated with potassium supplementation did not eliminate the advantage of diuretics. Treatment costs to prevent major hypertensive complications are much lower with diuretics and β-blockers than with ACEI, CCB, or α-blockers, especially in middle-aged patients.