Economic outcomes in the Study of Myocardial Perfusion and Coronary Anatomy Imaging Roles in Coronary Artery Disease registry: the SPARC Study

Abstract

Objectives: The goal of this study was to compare the economic outcomes of patients undergoing different noninvasive tests to evaluate suspected coronary artery disease (CAD).

Background: Evaluation of noninvasive tests is shifting to an assessment of their effect on clinical outcomes rather than on their diagnostic accuracy. Economic outcomes of testing are particularly important in light of rising medical care costs.

Methods: We used an observational registry of 1,703 patients who underwent coronary computed tomography angiography (CTA) (n = 590), positron emission tomography (PET) (n = 548), or single-photon emission computed tomography (SPECT) (n = 565) for diagnosis of suspected CAD at 1 of 41 centers. We followed patients for 2 years, and documented resource use, medical costs for CAD, and clinical outcomes. We used multivariable analysis and propensity score matching to control for differences in baseline characteristics.

Results: Two-year costs were highest after PET ($6,647, 95% confidence interval [CI]: $5,896 to $7,397), intermediate after CTA ($4,909, 95% CI: $4,378 to $5,440), and lowest after SPECT ($3,965, 95% CI: $3,520 to $4,411). After multivariable adjustment, CTA costs were 15% higher than SPECT (p < 0.01), and PET costs were 22% higher than SPECT (p < 0.0001). Two-year mortality was 0.7% after CTA, 1.6% after SPECT, and 5.5% after PET. The incremental cost-effectiveness ratio for CTA compared with SPECT was $11,700 per life-year added, but was uncertain, with higher costs and higher mortality in 13% of bootstrap replications. Patients undergoing PET had higher costs and higher mortality than patients undergoing SPECT in 98% of bootstrap replications.

Conclusions: Costs were significantly lower after using SPECT rather than CTA or PET in the evaluation of suspected coronary disease. SPECT was economically attractive compared with PET, whereas CTA was associated with higher costs and no significant difference in mortality compared with SPECT.

Keywords: costs and cost analysis; health services research; outcomes research.