The Accreditation Council for Graduate Medical Education recommended reducing the number of hours residents could work from 24 to 16, but researchers say the change did not result in much more sleep for the doctors.
First author Dr. Srijan Sen, a psychiatrist at the University of Michigan, Dr. Sudha Amarnath, a resident in the radiation oncology program at the University of Washington, and colleagues said the study involved 2,300 doctors in their first year of residency at about a dozen U.S. hospital systems.
The study, published in Internal Medicine, found after work hours went down in 2011, sleep hours didn't go up significantly, and the percentage of residents reporting that had committed medical errors that harmed patients rose.
Many interns entering after the new work hour restrictions said they felt that they were expected to do the same amount of work as in previous years, but in a more limited amount of time, leading to more harried and tiring work schedules despite working fewer hours, Amarnath said.
"Overall, they felt that there was less 'down time' during the work day compared to pre-2011 work schedules, which may partially explain some of the unexpected findings," Amarnath said in a statement.
Study co-author Dr. Breck Nichols of the University of Southern California, said in 2000 a typical call day lasted 36 hours.
"We have very specifically reduced that for interns from 36 hours to 30 hours in 2003, and now with the latest 2011 work hours change it has been reduced even further to 16 hours," Nichols said. "For most programs the significant reduction in work hours has not been accompanied by any increase in funding to offload the work. The end result is that current interns have about 20 less hours each week to complete the same or only slightly less work. We should not be surprised that giving interns less time to complete the same amount of work would increase their errors as well."