Treating mild to moderate hypertension: cost-effectiveness and policy implications.

Results from major clinical trials reported during the 1980s have led to renewed debate about the costs and benefits of treating mild to moderate hypertension. There is general agreement that existing cost-effectiveness analyses of antihypertensive therapy are outdated, and in need of reappraisal. Based on the pooled results of clinical trials, the benefits of treating mild to moderate hypertension [diastolic blood pressure (DBP) of 90-114 mm Hg] were re-examined. Using actuarial methods and estimates of health state utilities, the benefits of treatment were expressed in "quality-adjusted life years" (QALYs). After lifelong treatment for hypertension, the gain in QALYs ranged from 1.8 to 11.5 months in men and from 2.5 to 11.3 months in women. The cost-effectiveness ratios ranged from $30,200 per QALY gained (for 50-year-old men with DBP of 110 mm Hg) to $547,700 per QALY gained (for 30-year-old women with DBP of 110 mm Hg), in 1988 New Zealand dollars, discounted at 5%. In several categories of patients, the analysis suggested a net negative impact on QALYs, i.e., the adverse effects of drug treatment outweighed the benefits. These results have policy implications for both resource allocation and clinical practice.