The cost-effectiveness of treating mild-to-moderate hypertension: a reappraisal

Abstract

The cost-effectiveness of treating mild-to-moderate hypertension (diastolic blood pressures, 90-114 mmHg) was evaluated using the latest available information on both costs and benefits. The net health care costs of lifelong treatment for hypertension, at a 5% discount rate, ranged from £1491 to £2752 in men and from £1568 to £2850 in women in New Zealand in 1988 (£1.00=$NZ 2.81). These figures take into account the savings in health care costs arising from stroke prevention. The net health care benefits, measured in quality-adjusted life years (QALYs) discounted at 5%, ranged from —2 days (a net negative effect of treatment) to 64 days in men and from —18 days to 35 days in women. The cost-effectiveness of antihypertensive therapy discounted at 5% (excluding categories of patients for whom the ratio was undefined due to a net negative effect of treatment on QALYs) ranged from £11058 to £63 760 per QALY gained in men and from £22 060 to £194 989 per QALY gained in women. Treatment was more cost-effective in men than in women, in older age groups and at higher levels of pretreatment diastolic blood pressure. The cost-effectiveness ratios were highly sensitive to the discount rate used (with the majority of ratios in women being undefined at a 10% discount rate) and the costs of the regimen used (diuretic monotherapy being the most cost-effective, followed by P-blockers, then angiotensin-converting enzyme inhibitors), as well as to the assumptions made about the impact of medication side effects on patient quality of life. These results call for a re-examination of resource allocation to antihypertensive treatment and point to the need to make assessments of the cost-effectiveness of alternative, non-pharmacological approaches to stroke prevention.