After malpractice caps, doctors ordered fewer invasive tests to diagnose heart attacks

A patient comes into a hospital emergency department, troubled by chest pain that comes and goes. The doctor asks some questions, draws on clinical experience, and orders a test to rule out — or in — a heart attack.

That test could be a stress test that tracks the patient with an electrocardiogram while running on a treadmill. Or it could be a more specific but also more invasive test: an angiography that reveals blocked coronary arteries on X-ray after the patient has been injected with dye.

It’s a judgment call. Heart attack symptoms can be ambiguous, and there are no clear guidelines on which test to try when. But a new study published Wednesday in JAMA Cardiology has found one factor that appears to sway a doctor’s behavior when diagnosing a heart attack: whether the state where he or she is practicing has enacted a law capping malpractice damages. These laws limit payments made to compensate plaintiffs for “pain and suffering.”

A research team from George Washington University showed that in nine states with new malpractice damage caps, physicians ordered 24 percent fewer angiographies as a first test than physicians in 20 states without such caps. In those new-cap states, doctors also ordered 21 percent fewer coronary angiographies as a follow-up and 23 percent fewer coronary procedures such as stenting, which other research says is sometimes an overused procedure.

“Cardiac care is always an area where the stakes are high if you make a mistake, and we know that misdiagnosis of a cardiac condition is a very common source of malpractice claims,” said Dr. Anupam Jena, an economist at Harvard Medical School who studies physician behavior and medical malpractice. He was not involved in this study. “Looking at whether physicians behave differently with respect to a workup of chest pain and seeing how that workup differs if they are less likely to be sued or face lower damages if they are sued — that question is really interesting.”

Limiting malpractice damages has been touted as a way to reduce health care spending, but multiple studies haven’t borne out that connection. The George Washington researchers say their study is among to first to see if malpractice laws have made a difference in “defensive medicine”: ordering expensive tests and procedures that may be only marginally beneficial to the patient.

For their study, the researchers looked at more than 36,000 doctors who evaluated patients with chest pain in nine states with new laws capping malpractice damages. They compared them to more than 39,000 doctors in 20 states without malpractice caps.

Overall testing rates didn’t change, but the kind of test doctors in new-cap states ordered did change. While stress tests are less invasive and less costly, they are also less definitive.

“The physicians were more willing to tolerate more clinical ambiguity after the caps were adopted,” said Ali Moghtaderi, an assistant research professor of clinical research and leadership at George Washington.

The researchers do note that nationally, cardiologists were beginning to move away from more intensive procedures after a large study concluded that one of those procedures, cardiac revascularization, should not be done for people whose chronic chest pain is stable. That study and others could have influenced doctors’ choices in new-cap states toward the end of their study period, which ended in 2013.  

“The findings are encouraging in the sense that the cardiologists seem to be practicing in ways that better comport with contemporary clinical practice guidelines,” said Michelle Mello, a professor of health research and policy at Stanford who studies the effect of health laws on patient outcomes. “The law change seems to be encouraging better practice.”

The next question to answer: How did those patients fare? Moghtaderi said he and his colleagues are working on that.

“This is a very relevant and important question. If physicians change their behavior, are there any consequences for the patient?”

Stanford’s Mello would also like to know what happened after doctors changed the way they ordered tests.

“I think it’s plausible the reduction in some of the more intensive procedures might be beneficial,” she said. “It’s also possible they might have missed some things that were not caught.”

This story has been updated to add comments from Michelle Mello.