Interns Like Limited Shift Hours, Training Directors Don’t

A new study finds no correlation between limited shift lengths and how medical residents spend their time, or how they score on tests of medical knowledge.

Limiting first-year medical residents to 16-hour work shifts gives them a better work-life balance and makes them happier, a new study shows.

However, residency training directors believe the curtailed hours, with no ability to flex for longer shifts, impedes medical training, according to the study which was published online in The New England Journal of Medicine.

Regardless of those concerns, the NEJM study—which tracked thousands of first-year residents in 63 internal medicine training programs nationwide—found no correlation between limited shift lengths and how medical residents spent their time, or how they scored on tests of medical knowledge.

"Many educators have worried that the shift work created by limited duty hours will undermine the training and socialization of young physicians," said principal investigator David Asch, MD, with the Perelman School of Medicine at the University of Pennsylvania, in notes accompanying the study.

"Educating young physicians is critically important to healthcare, but it isn’t the only thing that matters. We didn't find important differences in education outcomes, but we still await results about the sleep interns receive and the safety of patients under their care," Asch said.

The arduous hours for medical residents were justified by training directors as a way to prepare new physicians for the rigors of the job, and to ensure continuity of care that can be disrupted by shift changes. Proponents of limited shift hours have argued that long hours lead to fatigue and errors.

In 2003, the Accreditation Council for Graduate Medical Education issued its first set regulations based on expert opinion—30-hour maximum shifts and 80-hour maximum workweeks—for all accredited residency programs. More stringent regulations were adopted in 2011 that limited interns to 16-hour shifts and more senior residents to 28-hour shifts.

Despite the findings that appear to support limited shifts, Asch said questions remain.    

"We created this study to simultaneously evaluate the effect of alternative duty hour policies on resident education, resident sleep and alertness, and patient safety," he said. "The part of this study being reported in the March 20 issue of the New England Journal of Medicine is about medical education. It will be essential to see the rest of the data before we know where to go next."

Asch said those results should be available early next year. 

Funding for the study was provided by the ACGME and the National Heart, Lung, and Blood Institute.