Physicians’ fears of malpractice lawsuits appear to drive them to order more diagnostic tests, even in states with medical liability damage caps, according to a new study in the Aug. 5 issue of Health Affairs.
The study, which linked survey data on physician perceptions of malpractice risk to their ordering data, found that physicians had higher rates of diagnostic imaging ordering for patients with lower back pain and headache if they were more concerned about their malpractice risk. But the researchers did not find that defensive ordering declined when states enacted tort reforms such as damage caps.
"Our paper suggests that physicians’ self-report of their defensive concerns may have a stronger impact than was previously suspected, but it definitely doesn’t answer the question of specifically how strong that effect is," said Dr. Emily Carrier, a senior health researcher at the Center for Studying Health System Change. Dr. Carrier is an emergency physician.
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A new study found physicians had higher rates of diagnostic imaging ordering for patients with lower back pain and headache if they were concerned about their malpractice risk.
The researchers examined the use of diagnostic tests, referrals to the emergency department, and admissions to the hospital for ambulatory patients who saw a physician with complaints of chest pain, headache, or lower back pain. The researchers said they chose these conditions because they represent a range of underlying problems, and because physicians have considerable discretion in how they treat these cases.
Patients with chest pain had a significantly higher chance of being referred to the emergency department, rather than having an outpatient stress test, if their physicians had a high or medium level of malpractice concern. The researchers also observed somewhat higher ordering rates for advanced imaging and hospitalization by physicians with higher malpractice concerns, but the figures were not significantly higher.
Headache patients whose physicians had high levels of malpractice concern were significantly more likely to receive advanced imaging than were those whose physicians had a low level of concern (11.5% versus 6.4%). But rates of conventional imaging and hospitalization were extremely low for headache patients and were not associated with the level of malpractice concern. Also, the researchers failed to find a significant association between the level of malpractice concern and referrals to the emergency department for headache patients.
Patients with lower back pain were more likely to receive both conventional and advanced imaging services if their physicians had high levels of concern about malpractice lawsuits, compared with patients whose physicians had fewer concerns. There was no significant difference in the likelihood that these patients would be admitted to the hospital for their complaints.
The study also found that damage caps don’t seem to be impacting defensive medicine practices.
When the researchers analyzed Medicare claims with the state data on the presence of medical liability damage caps, they found that services often went up in states with caps. The finding may be a case of "reverse causality," the researchers said. In states where there are high levels of defensive medicine, lawmakers are more likely to adopt a damage cap.
Dr. Carrier said she suspects that advocates on both sides of the medical liability reform debate will find data points to bolster their arguments from the study. But she hopes that there will be more study of alternative tort reform strategies such as "safe harbors" for physicians who follow evidence-based practice guidelines.
"We certainly aren’t coming down on one side or the other," she said. "We’re just showing that given our data, we may need to rethink some previous conclusions and find a different approach."
Another area where the researchers did not find a clear association was in the emergency department. There was no significant link observed between emergency physicians’ levels of malpractice concern and the services they ordered when patients came to the emergency department first.
"It’s possible that at this point in specialties like emergency medicine, defensive care has been so baked into training and routine that even people who think they are not very defensive are still being defensive," Dr. Carrier said.
The retrospective study includes Medicare Part A and B claims data on nearly 1.9 million beneficiaries who received services from 2007 to 2009. The claims are linked to data from the 2008 Center for Studying Health System Change Health Tracking Physician Survey, which includes concerns about malpractice suits.
Survey data on physician perceptions of their malpractice risk have been published before, but they have not been linked to claims data showing physicians’ actual ordering behavior.