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More aggressive malpractice climates don't necessarily protect patients from surgical complications, a new study suggests

Supporters of medical malpractice laws that make it easier for patients to sue doctors say these protections are necessary to improve care. But in the current study, the risk of litigation didn't translate into better outcomes, said study leader Dr. Karl Bilimoria, director of the Surgical Outcomes and Quality Improvement Center at Northwestern University's Feinberg School of Medicine in Chicago.

"It doesn't really work - malpractice environment doesn't influence doctors to provide better care," Bilimoria said by email. "Rather, it may lead to defensive medicine practices where more tests and treatments are ordered unnecessarily just to try to minimize malpractice risk."

Bilimoria and colleagues examined state-specific data on medical malpractice insurance premiums, average award size and the number of claims for every 100 physicians in each state as of 2010.

They also examined 2010 data on the odds of death, complications or repeat operations within 30 days surgery for patients insured by fee-for-service Medicare, the U.S. health program for the elderly and disabled.

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The study included data on about 890,000 Medicare members who received care at almost 3,200 hospitals nationwide. Half were at least 74 years old.

During the study period, the average annual malpractice premium for general surgeons was roughly $47,000.

More aggressive malpractice laws and larger malpractice awards did not reduce patients' risk for any of the postoperative complications studied, the researchers report in the Journal of the American College of Surgeons. No individual state malpractice law was consistently associated with improved post-operative outcomes.

Instead, in states where doctors faced greater risk from malpractice claims, patients were 22 percent more likely to develop sepsis, a potentially life-threatening bloodstream infection, the study found.

Patients in states where doctors had the most litigation risk were also 9 percent more likely to develop pneumonia, 15 percent more likely to suffer acute kidney failure and 18 percent more likely to have gastrointestinal bleeding.

The study can't prove how specific laws cause specific outcomes, the authors note. It's also not clear from the results whether patient outcomes led to certain state laws or if the reverse was true, and certain state policy shifts created different outcomes for patients.

Still, the results add to a growing body of evidence suggesting that tort reforms aren't associated with better outcomes, said Michelle Mellow, a law professor at Stanford University in California who wasn't involved in the study.

"This study contributes further evidence that liability pressure doesn't spur doctors to get better results for patients, but neither does adopting reforms to limit liability," Mellow said by email.

It's not surprising that the study didn't find a consistent link between malpractice environment and surgical complications because these associations can be specific to certain procedures or fields within medicine, said Dr. William Sage, a law and medicine professor at the University of Texas at Austin who wasn't involved in the study.

"The only things that are really clear are that too many patients are injured, too few of those receive compensation, and the whole process is slow and miserable for both physicians and patients," Sage said by email. "We also know that tort reforms capping damages at low amounts discourage most people from suing because lawyers won't take the cases, which in turn reduces the malpractice insurance premiums that physicians pay - both of which are pretty obvious."

Some previous research suggests that one type of law, that compares doctors' results against national averages, can help improve outcomes in below-average states, said Dr. Anupam Jena, a researcher at Harvard University in Boston who wasn't involved in the study.

"Changing the standards against which physicians are judged, either by ensuring that all states adopt national standard laws, or using administrative courts that hold physicians to a pre-specified clinical standard, are ways that I think the malpractice system can be leveraged to improve quality," Jena said by email.