Abstract 11670: Using the Coronary Calcium Score to Guide Statin Therapy: A Cost-Effectiveness Analysis

Abstract

INTRODUCTION: The coronary artery calcium (CAC) score, measured by CT scan, is a very strong predictor of coronary heart disease (CHD) events and could be used to help decide when to prescribe statins, but it’s unclear whether such a strategy would be cost-effective.

HYPOTHESIS: Cost-effectiveness of CAC testing will depend on the cost of statins

METHODS: Using an established CHD simulation model, we systematically compared “Test-and-Treat” strategies with different thresholds (>0, >100, or >300) against “Treat All” and “Treat None” strategies. Efficacy and adverse effect estimates for statins were derived from systematic reviews, and were applied for the first 10 years of the simulation according to strategy; after 10 years, all received statins, with accrual of healthcare costs and quality-adjusted life-years (QALYs) over a lifetime horizon. CAC score distributions were modeled as dependent on age, sex and CHD risk factors, and were associated with CHD relative risks of 3.6 (for CAC=1-100), 7.7 (101-300), and 9.7 (>300) vs. CAC=0. We focused on 45 yo men and 55 yo women with CAC testing costs=$218, and used a societal willingness-to-pay threshold of <$50,000/QALY.

RESULTS: The cost-effectiveness of CAC testing was highly dependent on the cost of statins (Figure). At lowest available generic prices ($4/month = $0.13/pill), Test-and-Treat strategies were preferred for 55 yo women at 2.5% 10-year risk and 45 yo men at 2.5-5% risk; at higher statin prices, Test-and-Treat strategies were cost-effective for higher and broader ranges of risk levels. If cheap statins are not available (< $0.44/pill in women, <$1.25/pill in men), our analysis suggests statins should not be used for primary prevention without first measuring CAC (Treat All costs >$50,000/QALY). The net cost of Test-and-Treat was lower than Treat All, even in high-risk generic-price statin scenarios, until CAC testing cost>$480/scan.

CONCLUSION: CAC testing can be an efficient way to target statin therapy.