Doctors with financial ties to MRI scanners tend to refer more knee pain patients for imaging, a new study says.
The study compared the results of 700 MRI scans of the knee. Half of the scans were ordered by doctors who made money 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 the MRI machines.
The same group of independent radiologists read all the scans. They weren't aware of the study at the time they reported their results.
To level the playing field even further, researchers only looked at knee patients who were making their first trip for an MRI. They excluded anyone who'd had previous imaging or surgery from the study.
"We were just looking at who is showing up to the clinic for first time and saying, 'my knee hurts' ", said study author Dr Matthew Lungren, radiologist duke university, Durham, North Carolina.
Patients referred by doctors who had a financial interest in the MRI tests were 33% 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 didn't 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 said, though he was also quick to point out that financial incentives often exist on a slippery slope. Doctors who have an MRI machine in their office may be quicker to order scans because it's easy and they can see the results quickly. Some doctors order more scans than others simply because that's how they were trained.
Whatever the reason, the scans are expensive for patients and insurers, and they may lead to more unnecessary tests and procedures if doctors find something that might need probing.
"Hopefully this will bring the discussion back around to how to cut waste out of the system," Lungren said.
The study findings, published online on 17 September in the journal Radiology, were not surprising to Dr David Levin, chairman emeritus of the department of radiology at Thomas Jefferson University, in Philadelphia.
Levin has focused much of his career on the problem of self-referral, but he was not involved in the current research.
"This issue has been studied for 40 years. There have been dozens of papers written on this subject, and every single one of them has shown that when self-referral of imaging is allowed, utilisation is going to skyrocket," Levin said.
A September 2012 report by the US Government Accountability Office, for example, found that doctors who owned imaging equipment ordered 80% more MRIs from 2004 to 2010, while doctors who didn't own scanners ordered about 12% more MRIs over the same period.
Laws poorly enforced
Several states have laws against self-referral, but most are poorly enforced.
Medicare patients are supposed to be protected against self-referral by federal legislation called the Stark Law, which prohibits doctors from having financial relationships with imaging centres in the same community.
But the law has a loophole, Levin said, which allows doctors to self-refer patients for imaging when the scanner is in the doctor's office.
"The law basically has no teeth, and patients have very little protection," Levin said.
So what can patients do to avoid expensive scans that might not be needed?
"I think the best thing to do is just ask: 'Do you have a financial relationship with the imaging that you're sending me to?'" study author Lungren said. "I feel like a physician should disclose that," he added.