A 2003 rule restricting the number of hours doctors-in-training can work each week didn’t affect the quality of care they provided once they were practicing independently, suggests a new study.

Restricting the hours doctors-in-training (commonly called "residents") worked each week may, in fact, have improved the outcomes for their high-risk patients, the researchers write in the journal Health Affairs.

“I think there are two issues that are very hotly debated in the field of medical education and workforce training,” said Dr. Anupam Jena, the study’s lead author from Harvard Medical School in Boston.

The first issue is about the quality of care patients receive from exhausted residents, he told Reuters Health. The second is about whether residents are being trained as well as before the rule took effect.

The 2003 rule was put in place by the Accreditation Council for Graduate Medical Education (ACGME) after rising concerns over patients being treated by exhausted residents. The rule reduced the residents’ work week to 80 hours. Individual shifts were capped at 30 hours.

ACGME again restricted hours in 2011, when they capped individual shifts at 16 hours for first-year residents and 28 hours for more senior residents.

Some studies have found that residents feel they are receiving less training as a result of the restrictions (see Reuters Health stories of Nov 2, 2012 here: reut.rs/1ut9mUU and of Jul 10, 2013 here: reut.rs/12iyk8r).

Another study found, however, that the 2003 rule did not lead to additional patient deaths, (see Reuters Health story of Apr 25, 2013 here: reut.rs/1utaqIr).

For the new study on doctor quality after the 2003 reforms, researchers used data collected between 2000 and 2009 on patient outcomes and doctors' training in the state of Florida.

Based on 4.6 million hospital admissions, the study team compared patient outcomes when treated by doctors trained before, during and after the 2003 rule. They also used data from a group of doctors with more than 10 years of experience to account for general improvements in hospital care that may have occurred during the study period.

Overall, the amount of time patients stayed in the hospital didn’t significantly change depending on whether doctors were trained before, during or after the 2003 rule.

Additionally, the proportion of patients who died did not significantly change depending on when the doctor was trained. In all cases, a little more than 3 percent of patients died.

The researchers did find that patients with complicated cases appeared to fare slightly better under doctors trained after the 2003 rule.

“What we find is among high-risk patients, when we do this exact same analysis, it appears physicians who are trained in this post-reform environment actually have better outcomes,” Jena said.

He said it could be that some unmeasured and unknown characteristic or event explains the results, or it's possible that doctors trained after the 2003 rule have better consolidated knowledge that improves outcomes for those difficult patients.

Dr. Sanjay Desai, who was not involved in the new study, told Reuters Health it also could be that recently graduated residents are more likely to keep up with training than more experienced doctors – though there’s no evidence of that.

He added that thanks to the system of checks and balances in place in current healthcare settings, such as electronic health records and electronic guidelines, it may be difficult to show a difference in mortality based on hours of training.

"It's difficult to imagine that duty hours would lead to such changes in the quality of physicians that it would lead to large-scale changes in patient health,” said Desai, director of the residency program at Johns Hopkins Hospital in Baltimore.

Jena said that the study found restricting duty hours doesn’t appear to affect patient outcomes. “If anything they may have actually improved for certain types of patients,” he said.

Desai said current duty hour restrictions are not based on research and there are two trials underway or being planned to test the effects of working longer or shorter hours.

"I think the policymakers want evidence... So far duty hour policy hasn't been informed by evidence,” he said. “They want these data so they can make the best informed decisions."