One of the great things about publishing in The New England Journal of Medicine is that old friends sometimes reconnect. “Congratulations on your NEJM article!” wrote Paul Gennis, MD, who was chair of emergency medicine at Jacobi Hospital in New York when I was a resident. “You may not have gotten the answer you were hoping for, but the answer you got is probably accurate.”

That was really nice, but I actually wasn’t hoping for any particular answer. From the perspective of a researcher, this was the rare study in which a negative result was as interesting as a positive one would have been. As a member of the emergency medicine community, I wasn’t disappointed either, nor do I believe that others should be.

The Research

Our recent study addressed the following question: do emergency physicians change their practice when the threat of malpractice suit is reduced?¹ In 2003, Texas changed its malpractice standard of care from “ordinary negligence” (ie, deviation from the “reasonableness” standard of customary practice) to “willful and wanton negligence.” In 2005, Georgia and South Carolina passed similar laws, changing their standard to “gross negligence.” This is a substantial change. To be found negligent under the revised standard, a plaintiff would need to prove that physicians had an “actual, subjective awareness” of “the likelihood of serious injury” but nevertheless proceeded with “conscious indifference” or “recklessness.” In other words, one would need to prove that physicians knew their actions or omissions would be more likely than not to cause serious harm, then carried them out anyway. Not impossible, but this is about as strong a reform as anybody has proposed.

Physicians strongly believe that “defensive practice” exists and, in fact, say that they practice defensively themselves. In one survey, 70 percent of emergency physicians polled said that they often practice defensively, meaning that they provide care or order tests they don’t believe patients need strictly because they fear lawsuits.² Advanced imaging (CT and MRI), hospital admission, and other diagnostic tests are the sort of items that are frequently called into question.

If fear of lawsuits is but one of a complex set of motivations for cautious behavior, then perhaps defensive medicine is really just medicine

Using Medicare claims, we evaluated the effect of the revised malpractice standard on the utilization of CT or MRI, hospital admission, and total per-visit ED charges. We used a quasi-experimental design, which compared the difference in each outcome in the reform states before and after the legislation was passed to the difference between the before and after periods in nearby states that didn’t pass reform (called a “difference in differences” design). The idea of a quasi-experiment is that assumptions are made explicit such that if you believe them, the results should be interpretable as if the patients had been randomly assigned to “exposure to the law” versus not. The key assumption here is that in comparing the pre-law and post-law time periods, the law itself is the only difference between reform and control states that would affect study outcomes.

The Results

The study results were surprising to some: we did not find evidence that changing the malpractice standard to gross negligence (or the equivalent) had any effect on practice. There was no discernable effect on rates of CT/MRI utilization or hospital admission. In two of three cases, total charges were not affected. In Georgia, reform was associated with a 3.4 percent reduction in average charges. These findings held true both in terms of the raw results and after adjusting for patient characteristics, hospital characteristics, and other factors.