Association of coronary CT angiography or stress testing with subsequent utilization and spending among Medicare beneficiaries

Abstract

Context: Coronary computed tomography angiography (CCTA) is a new noninvasive diagnostic test for coronary artery disease (CAD), but its association with subsequent clinical management has not been established.

Objective: To compare utilization and spending associated with functional (stress testing) and anatomical (CCTA) noninvasive cardiac testing in a Medicare population.

Design, setting, and patients: Retrospective, observational cohort study using claims data from a 20% random sample of 2005-2008 Medicare fee-for-service beneficiaries 66 years or older with no claims for CAD in the preceding year, who received nonemergent, noninvasive testing for CAD (n = 282,830).

Main outcome measures: Cardiac catheterization, coronary revascularization, acute myocardial infarction, all-cause mortality, and total and CAD-related Medicare spending over 180 days of follow-up.

Results: Compared with stress myocardial perfusion scintigraphy (MPS), CCTA was associated with an increased likelihood of subsequent cardiac catheterization (22.9% vs 12.1%; adjusted odds ratio [AOR], 2.19 [95% CI, 2.08 to 2.32]; P < .001), percutaneous coronary intervention (7.8% vs 3.4%; AOR, 2.49 [2.28 to 2.72]; P < .001), and coronary artery bypass graft surgery (3.7% vs 1.3%; AOR, 3.00 [2.63 to 3.41]; P < .001). CCTA was also associated with higher total health care spending ($4200 [$3193 to $5267]; P < .001), which was almost entirely attributable to payments for any claims for CAD ($4007 [$3256 to $4835]; P < .001). Compared with MPS, there was lower associated spending with stress echocardiography (-$4981 [-$4991 to -$4969]; P < .001) and exercise electrocardiography (-$7449 [-$7452 to -$7444]; P < .001). At 180 days, CCTA was associated with a similar likelihood of all-cause mortality (1.05% vs 1.28%; AOR, 1.11 [0.88 to 1.38]; P = .32) and a slightly lower likelihood of hospitalization for acute myocardial infarction (0.19% vs 0.43%; AOR, 0.60 [0.37 to 0.98]; P = .04).

Conclusion: Medicare beneficiaries who underwent CCTA in a nonacute setting were more likely to undergo subsequent invasive cardiac procedures and have higher CAD-related spending than patients who underwent stress testing.