Background: Because of diagnostic uncertainty, patients with symptoms suggestive of obstructive coronary artery disease (CAD) are referred at high rates to cardiologists and advanced cardiac testing. This evaluation process may also expose patients to appreciable costs and health risks. A previously validated, blood-based test incorporating age, sex and genomic expression into an algorithmic score (1-40) has shown clinical validity in assessing the likelihood of obstructive CAD (≥50% luminal diameter stenosis by quantitative coronary angiography) early in the cardiac workup. This test has also shown clinical utility in association with decision making around cardiac referrals and helping clinicians determine the current likelihood of obstructive CAD in symptomatic patients.
Hypothesis: We hypothesized that use of the age/sex/gene expression score (ASGES) test would influence cost of care in the diagnosis and management of symptomatic patients with suspected obstructive CAD.
Methods: The prospective PRESET Registry (NCT01677156) enrolled stable, non-acute adult patients presenting with symptoms suggestive of obstructive CAD to 21 US primary care practices from September 2012 to August 2014. Primary care clinicians provided pre- and post-ASGES diagnosis and evaluation plans for each patient. Demographics, clinical factors, and ASGES results (predefined as low [ASGES ≤ 15] or elevated [ASGES > 15]) were collected, as were management plans post-ASGES testing, including referrals to cardiology or further functional/anatomic testing. The economic analysis for cost of care after ASGES testing was based on the cost of cardiovascular-related tests, invasive procedures, office visits, emergency room visits, and hospital admissions during 1-year follow-up.
Results: This sub-analysis cohort included 560 patients, with 50% females and median age 56 years. Patients had a median ASGES score of 18, with 246 (44%) patients with ASGES < 15. The mean cost of care for patients in the year following ASGES testing was $234 (SD ±$707) in the low ASGES versus $1,296 (SD ±$5230) in the elevated ASGES group (p=0.03 by Wilcoxon rank test). Multivariate analysis incorporating patient demographics and clinical covariates showed that low ASGES was associated with a 51% reduction in cost of follow-up care compared to elevated ASGES group (p<0.001 by log-linear regression).
Conclusion: In this community-based cardiovascular registry, the ASGES influenced costs in the evaluation of patients with suspected obstructive CAD. Low score patients had approximately half the cardiovascular costs of elevated score patients in one year follow-up. Our work provides evidence supporting the economic value of using precision medicine in the delivery of cardiovascular care.