By Scott Harris

A new study found that less-experienced physicians tend to provide more costly care per patient than their more veteran counterparts. An underlying cause of the difference, however, eluded researchers.

The study, published in the November edition of the journal Health Affairs, found that out of 12,116 physicians in the Massachusetts Health Quality Partners database spanning 27 specialties, physicians with fewer than 10 years of experience had 13.2 percent higher overall costs than physicians with 40 or more years of experience.

“We found no association between costs and other physician characteristics, such as having had malpractice claims or disciplinary actions, board certification status, and the size of the group in which the physician practices,” the study authors wrote.

Lead study author Ateev Mehrotra, MD, MPH, an associate professor of medicine at University of Pittsburgh School of Medicine and a policy analyst at the RAND Corporation, said he was not searching for, nor did he expect, the study’s main finding.

“Malpractice and defensive medicine are where I thought the differences would be, but experience had by far the strongest relationship to cost,” Mehrotra said. “In retrospect, the relationship between spending and experience may not be so surprising.”

A possible explanation, though, remains mysterious, despite efforts to identify it.

“One idea was that ordering tests will be more familiar to younger physicians,” Mehrotra said. “But we didn’t find any evidence of that. Spending went up not just with things like imaging and other tests or procedures that are commonly ordered, but across the board. Then there was a thought about a new relationship between young physicians and attendings, or between the young doctor and a new hospital. But that didn’t really bear out, either.”

Observing that the study covered only doctors practicing in Massachusetts, Mehrotra said more study is needed. He added that cost profiles and their bearing on variations in care could be an important avenue for investigation not just in the research arena but also, potentially, in medical education, practice, or public policy.

“There is a moral hazard problem at work,” Mehrotra said. “If you don’t know the cost of something, you’re more likely to use it. One question that has come up is whether making more information available around the costs of care would lead to more judicious use of resources. When I’m in the hospital, I don’t know what things cost. That is an area that would be good to explore. Physicians probably have no clue about the costs of the tests and procedures they are ordering.”