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

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.