Study: Knee MRIs Often Driven by Profit

A study conducted by Duke University Medical Center clinicians found that doctors are more likely to order potentially unnecessary knee imaging when they have a financial stake in the equipment.

MRI scans turned up negative in significantly more patients referred by physicians with an ownership interest in the imaging equipment than by those without any financial incentive (33 percent vs. 25 percent, P=0.016), Matthew P. Lungren, M.D., and colleagues concluded.

Lungren’s study compared the results of 700 MRI scans of the knee. Half of the scans were ordered by doctors who profited from the tests because they owned the imaging equipment — a practice known as self-referral. The other half of the scans were ordered by doctors with no financial ties to MRI machines. To further level the playing field, researchers limited the study to first-time knee patients with no prior MRIs or surgeries.

“We were just looking at who is showing up to the clinic for the first time and saying, ‘my knee hurts,'” Lungren, a radiologist at Duke University, in Durham, N.C., told HealthDay News.

A group of independent radiologists unaware of the study read all the scans and reported their results. Patients referred by doctors who had a financial interest in the MRI tests were 33 percent more likely to have a normal result than patients whose doctors had no stake in the scans. Radiologists read 117 of 350 scans to be normal in the group with doctors who made money off of the scans, compared with 88 normal readings of 350 scans in the group where doctors did not get a cut of the testing fee.

“The concern, of course, that everyone is thinking about is: Are these being ordered to generate profit?” Lungren asked, noting that motives often are difficult to determine. Doctors with office MRI machines, for example, may order scans for quick and easy analysis while others may favor them from their training.

Regardless of the reason, MRI scans are expensive for patients and insurers, and they could lead to more unnecessary tests and procedures, particularly if doctors find something that needs further clarity.

“Hopefully this will bring the discussion back around to how to cut waste out of the system,” Lungren said.

The study findings, published online in the journal Radiology, couldn’t prove intentional overuse due to a profit motive, but the possibility might be worthy of consideration by government and third-party payers, the researchers suggested.

“Despite the limitations, we believe that the inherent conflict of interest present when physicians both order and then perform and collect fees on the basis of the acquisition of MR imaging examinations is an important factor to consider whenever the matter of health care cost is raised,” they wrote.

Diagnostic imaging’s contribution to the growth in healthcare spending has been leveling off overall, but “self-referral in advanced diagnostic imaging continues to increase among nonradiologist physicians and has been shown to be a major contributor to higher utilization and costs of imaging,” Lungren and his cohorts pointed out.