Association Between Physician Billing and Cardiac Stress Testing Patterns Following Coronary Revascularization

Study Questions:

What is the association between patients undergoing cardiac stress imaging after coronary revascularization and the pattern of stress imaging billing of the physician practice providing their follow-up care?

Methods:

Using data from a national health insurance carrier, 17,847 patients were identified between November 1, 2004, and June 30, 2007, who had coronary revascularization and an index cardiac outpatient visit more than 90 days following the procedure. Based on overall billings, physicians were classified as billing for both technical (practice/equipment) and professional (supervision/interpretation) fees, professional fees only, or not billing for either. Logistic regression models were used to evaluate the association between physician billing and use of stress testing, after adjusting for patient and other physician factors. The primary outcome measure was the incidence of nuclear and echocardiographic stress tests within 30 days of an index cardiac-related outpatient visit.

Results:

The overall cumulative incidence of nuclear or echocardiography stress testing within 30 days of the index cardiac-related outpatient visit following revascularization was 12.2% (95% confidence interval [CI], 11.8%-12.7%). The cumulative incidence of nuclear stress testing was 12.6% (95% CI, 12.0%-13.2%), 8.8% (95% CI, 7.5%-10.2%), and 5.0% (95% CI, 4.4%-5.7%) among physicians who billed for technical and professional fees, professional fees only, or neither, respectively. For stress echocardiography, the cumulative incidence of testing was 2.8% (95% CI, 2.5%-3.2%), 1.4% (95% CI, 1.0%-1.9%), and 0.4% (95% CI, 0.3%-0.6%) among physicians who billed for the technical and professional fees, professional fees only, or neither, respectively. Adjusted odds ratios (ORs) of nuclear stress testing among patients treated by physicians who billed for technical and professional fees and professional fees only were 2.3 (95% CI, 1.8-2.9) and 1.6 (95% CI, 1.2-2.1), respectively, compared with those patients treated by physicians who did not bill for testing (p < 0.001). The adjusted OR of stress echocardiography testing among patients treated by physicians billing for both or professional fees only were 12.8 (95% CI, 7.6-21.6) and 7.1 (95% CI, 4.0-12.9), respectively, compared with patients treated by physicians who did not bill for testing (p < 0.001).

Conclusions:

The authors concluded that nuclear stress testing and stress echocardiography testing following revascularization were more frequent among patients treated by physicians who billed for technical fees, professional fees, or both compared with those treated by physicians who did not bill for these services.

Perspective:

This novel study examined the association between physician billing and patterns of stress testing after coronary revascularization, and reported that patients treated by practices who billed for the technical and professional fees were significantly more likely to order nuclear stress imaging after revascularization relative to those who did not directly bill for these tests. This association between physician billing status for stress tests and testing frequency persisted after adjusting for patient and physician factors that influence testing. These findings highlight the need for broader application of the American College of Cardiology Foundation appropriate use criteria in clinical practice to eliminate/minimize any possible influence of financial incentives on the decision to perform cardiac stress testing after revascularization. Recent policy proposals such as global payments for care, accountable care organizations, and value-based purchasing arrangements may also mitigate the influence of billing status on diagnostic testing in select patient populations.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and Imaging, Angiography, Echocardiography/Ultrasound, Nuclear Imaging

Keywords: Odds Ratio, Value-Based Purchasing, Follow-Up Studies, Echocardiography, Stress, Diagnostic Imaging, National Health Programs, Fees and Charges, Outpatients, Coronary Angiography, Accountable Care Organizations, Confidence Intervals, United States, Logistic Models, Exercise Test


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