Cost-Effectiveness of Screening for Carotid Stenosis in Asymptomatic Persons

Abstract

Background: The Asymptomatic Carotid Atherosclerosis Study (ACAS) showed that carotid endarterectomy was beneficial for symptom-free patients with carotid stenosis of 60% or more. This finding raises the question of whether widespread screening to identify cases of asymptomatic carotid stenosis should be implemented.

Objective: To determine whether a screening program to identify cases of asymptomatic carotid stenosis would be a cost-effective strategy for stroke prevention.

Design: Cost-effectiveness analysis using published data from clinical trials.

Setting: General population of asymptomatic 65-year-old men.

Intervention: Patients who were screened for carotid disease with duplex Doppler ultrasonography were compared with patients who were not screened. If ultrasonography found significant carotid stenosis (≥ 60%), disease was confirmed by angiography before carotid endarterectomy was done.

Measurements: Quality-adjusted life-years, costs, and marginal cost-effectiveness ratios.

Results: When the conditions and results of ACAS were modeled and it was assumed that the survival advantage produced by endarterectomy would last for 30 years, the lifetime marginal cost-effectiveness of screening relative to no screening was $120 000 per quality-adjusted life-year. Sensitivity analysis showed that marginal cost-effectiveness decreased to $50 000 or less per quality-adjusted life-year only under implausible conditions (for example, if a free screening instrument with perfect test characteristics was used or an asymptomatic population with a 40% prevalence of carotid stenosis was found).

Conclusions: Surgery offers a real but modest absolute reduction in the rate of stroke at a substantial cost. A program to identify candidates for endarterectomy by screening asymptomatic populations for carotid stenosis costs more per quality-adjusted life-year than is usually considered acceptable.