Objective To assess the cost-effectiveness of cardiac CT compared with exercise stress testing (EST) in improving the health-related quality of life of patients with stable chest pain.

Methods A cost–utility analysis alongside a single-centre randomised controlled trial carried out in Northern Ireland. Patients with stable chest pain were randomised to undergo either cardiac CT assessment or EST (standard care). The main outcome measure was cost per quality adjusted life year (QALY) gained at 1 year.

Results Of the 500 patients recruited, 250 were randomised to cardiac CT and 250 were randomised to EST. Cardiac CT was the dominant strategy as it was both less costly (incremental total costs −£50.45; 95% CI −£672.26 to £571.36) and more effective (incremental QALYs 0.02; 95% CI −0.02 to 0.05) than EST. At a willingness-to-pay threshold of £20 000 per QALY the probability of cardiac CT being cost-effective was 83%. Subgroup analyses indicated that cardiac CT appears to be most cost-effective in patients with a likelihood of coronary artery disease (CAD) of <30%, followed by 30%–60% and then >60%.

Conclusions Cardiac CT is cost-effective compared with EST and cost-effectiveness was observed to vary with likelihood of CAD. This finding could have major implications for how patients with chest pain in the UK are assessed, however it would need to be validated in other healthcare systems.

Trial registration number (ISRCTN52480460); results.