Financial Stake Brings More Cardiac Stress Imaging

Physicians who billed for nuclear and echocardiographic stress imaging tests were more likely to prescribe such tests after coronary revascularization than those who did not bill for these services, according to a study in the November 9 issue of the Journal of the American Medical Association.

The study’s findings track with those of a recent American Journal of Roentgenology report concluding that nonradiologist physicians with a financial interest in imaging means were as much as 49 percent more likely to order imaging as those with no financial interest.

In the current study, Bimal R. Shah, MD, MBA, of Duke University Medical Center, and colleagues examined 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. Using data from a national health insurance carrier, the team identified 17,847 patients who had coronary revascularization and a cardiac outpatient visit more than 90 days following the procedure between November 2004 and June 2007.

Based on overall billings, physicians were classified into three categories: physicians who routinely billed for technical (practice/equipment) and professional (supervision/ interpretation) fees; physicians who routinely billed for professional fees only; and physicians who did not routinely bill for either service. They evaluated the association between physician billing and use of stress testing, adjusting for patient and other physician factors.

The team found that physicians who billed for technical and professional fees for nuclear stress testing and those who billed for professional fees only were more likely to perform nuclear stress tests following revascularization than those not billing (13.3 percent and 9.4 percent vs. 5.3 percent). Physicians who billed for technical and professional fees for stress echocardiography testing or professional fees only were more likely to perform stress echocardiography testing following revascularization than those not billing (3.1 percent and 1.5 percent vs. 0.5 percent).

The authors wrote that although current American College of Cardiology Foundation’s appropriateness utilization criteria (AUC) do not recommend routine use of early stress testing following coronary revascularization, they found that 12 percent of patients with a cardiac-related outpatient visit at least three months after revascularization underwent a stress test within 30 days of their visit. Also, up to one in 10 patients who were not coded as having symptoms at their outpatient visit still underwent stress testing.

“Discretionary stress testing after revascularization has potential financial and clinical disadvantages for patients, including the costs of the tests, the exposure to ionizing radiation as well as potential down-stream costs, and consequences from following up false-positive test results,” Shah and colleagues wrote. “These data suggest the need for broader application of AUC to minimize the possible influence of financial incentives on the decision to perform cardiac stress testing after revascularization.”

In an accompanying editorial, Brent K. Hollenbeck, MD, and Brahmajee K. Nallamothu, MD, MPH, of the University of Michigan wrote that, despite the implementation of measures such as the Stark laws designed to remove the financial conflicts of interest from physician decision making for clinical laboratory tests and other ancillary services, the problem persists.

“The study by Shah et al highlights the principal risk of in-office imaging. By examining this phenomenon in a clinical context generally considered to be ‘inappropriate’ - namely, routine cardiac stress imaging after coronary revascularization - the investigators have demonstrated the persistence of financial conflicts of interest as a driver of utilization,” Hollenbeck and Nallamothu said. “The truism ‘if you provide a service, you’re more likely to provide a service’ apparently has not changed over the years.”