Providing more care than necessary may work to lower a doctor’s risk of being accused of malpractice, suggests a new U.S. study.

Although the results can’t prove extra expenditures are due to so-called defensive medicine, the researchers found that doctors in Florida who provided the most costly care between 2000 and 2009 were also least likely to be sued between 2001 and 2010.

“By no means would I consider it to be conclusive, but it does signal to us that defensive medicine could work in lowering malpractice risk, but more research is needed to know if that’s true or not,” said lead author Dr. Anupam Jena, of Massachusetts General Hospital and Harvard Medical School in Boston.

He and his colleagues write in The BMJ that critics of the U.S. malpractice system suggest it encourages defensive medicine, which is when doctors provide more healthcare than necessary in order to stave off lawsuits.

“If you ask physicians what’s the number one concern they have when you talk to them about their careers, I would say malpractice will come up as one of their top concerns,” Jena said.

While it’s commonly accepted that doctors practice defensive medicine, the researchers write, no studies have been able to answer whether the practice actually reduces the risk of lawsuits.

For the new study, Jena’s team examined data from Florida hospitals, looking specifically at whether doctors within seven medical specialties were less likely to face lawsuits in the year following one when they racked up higher than average hospital charges.

Overall, they had data on nearly 25,000 doctors who oversaw about 18.3 million hospital admissions and faced over 4,300 malpractice claims.

“If you look at doctors who spend more in a given specialty, higher spending physicians get sued less often than low spending physicians,” Jena said of the findings.

For example, an internist whose average hospitalization cost about $20,000 (the lowest spending group) faced a 1.2 percent probability of being sued the following year. That compared to a 0.3 percent probability of being sued if the internist’s average hospitalization cost about $39,000 (the highest spending group).

Researchers also found a lower probability of facing a lawsuit among obstetricians following a year when they performed a high number of cesarean sections, which critics say are often done defensively.

Even when looking at individual obstetricians, the researchers found that one’s probability of facing lawsuits changed with the number of c-sections he or she performed. As a doctor performed more C-sections, their risk came down.

“Putting all this together, the findings say higher spending by physicians is associated with lower claims,” Jena said. “What that means is more difficult to say.”

The study’s findings are limited, because the researchers did not have much information on the severity of the patients’ illnesses. They also can’t prove the higher spending is actually a result of practicing defensive medicine.

“The only thing you can say with certainty is there is a correlation between spending and a risk of being named as a defendant on a lawsuit, but that’s a correlation without causation,” said Dr. Daniel Waxman, of RAND Corporation in Santa Monica, California.

“Yes, doctors are afraid of lawsuits, but they’re also afraid of looking bad,” said Waxman, who has researched defensive medicine but was not involved in the new study. “There are other motivations to do more as well.”

For example, he said, obstetricians may perform more C-sections because they believe it’s best for their patients.

As for whether defensive medicine actually leads to fewer lawsuits, Waxman said the data used in the study can’t answer that question.

“From a research direction, we want to better understand why we’re finding this link,” he added.