Outcomes After Coronary Artery Calcium and Other Cardiovascular Biomarker Testing Among Asymptomatic Medicare Beneficiaries
Background—Biomarkers improve CVD risk prediction but their comparative effectiveness in clinical practice is not known. We sought to compare utilization, spending, and clinical outcomes in asymptomatic Medicare beneficiaries evaluated for cardiovascular disease (CVD) with coronary artery calcium (CAC) or other cardiovascular risk markers.
Methods and Results—We used a 20% sample of 2005-2011 Medicare claims to identify fee-for-service beneficiaries aged >=65.5 years with no CVD claims in the prior 6 months. We matched on propensity score CAC patients with patients who received hs-CRP (n=8,358) or lipid screening (n=6,250). CAC was associated with increased noninvasive cardiac testing within 180 days (hazard ratio [HR] 2.22, 95% CI 1.68-2.93, p < 0.001, versus hs-CRP; HR 4.30, CI 3.04-6.06, p < 0.001, versus lipid screening), as well as increased coronary angiography and revascularization. Over three years follow-up, CAC was associated with higher CVD-related spending ($6,525 versus $4,432 for hs-CRP, p < 0.001; $6,500 versus $3,073 for lipid screening, p < 0.001), and fewer CVD-related events compared with hs-CRP (HR 0.74, CI 0.58-0.94, p=0.017) but not compared with lipid screening (HR 0.84, CI 0.64-1.11, p=0.23).
Conclusions—CAC testing among asymptomatic Medicare beneficiaries was associated with increased use of cardiac tests and procedures, higher spending, and slightly improved clinical outcomes compared with hs-CRP testing.
- Received October 31, 2013.
- Accepted April 23, 2014.