Association between physician billing and cardiac stress testing patterns following coronary revascularization

Context: The degree to which financial factors may influence use of cardiac stress imaging procedures is unknown. Objective: To examine the association of physician billing and nuclear stress and stress echocardiography testing following coronary revascularization. Design, Setting, and Patients: 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. Main Outcome Measures: 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% 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<.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<.001). Conclusion: 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.