Patient safety, resident sleep do not appear to differ with flexible vs. standard duty hours

Sixty-three U.S. internal medicine residency programs were randomly assigned to follow standard duty-hour policies mandating 16-hour shifts and an 80-hour workweek, or flexible policies, with an 80-hour workweek but no limits on shift length or mandatory time off between shifts.


Patient safety outcomes and resident sleep loss do not appear to be affected by flexible or standard duty hours, according to two recent studies from a randomized clinical trial.

The iCOMPARE (Individualized Comparative Effectiveness of Models Optimizing Patient Safety and Resident Education) trial assessed patient safety and resident sleep and alertness at 63 U.S. internal medicine residency programs during the 2015-2016 academic year. The programs were randomly assigned to follow the Accreditation Council for Graduate Medical Education (ACGME)'s standard 2011 duty-hour policies mandating 16-hour shifts and an 80-hour workweek, or flexible policies, where an 80-hour workweek was maintained but no limits were placed on shift length or mandatory time off between shifts. A study reporting the effects on patient safety and a study reporting on sleep and alertness outcomes were published March 7 by the New England Journal of Medicine. iCOMPARE was funded by the National Heart, Lung, and Blood Institute and by ACGME.

Thirty-two programs were assigned to the flexible group, and 31 were assigned to the standard group. In the first study, the primary outcome was the change in unadjusted 30-day mortality before and during the trial year, according to Medicare claims, while changes in five other measures of patient safety and risk-adjusted outcomes were the secondary outcome measures. The prespecified noninferiority margin was 1 percentage point for differences in changes between the flexible and standard programs. Patients in the flexible programs had a noninferior change in mortality versus those in the standard programs (12.5% in the trial year and 12.6% in the pretrial year vs. 12.2% in the trial year vs. 12.7% in the pretrial year, respectively). Unadjusted rate of readmission at seven days, other indicators of patient safety, and Medicare payments were also within the noninferiority margin, while 30-day readmissions and prolonged hospital stay were not. Findings were similar for risk-adjusted measures, the study authors said.

In the second study, sleep duration and morning sleepiness and alertness were compared for noninferiority between 205 interns in six flexible programs and 193 interns in six standard programs. The outcome measures included sleep duration as measured with actigraphy, the Karolinska Sleepiness Scale, and a Psychomotor Vigilance Test. Data were obtained over 14 days for both groups. Average sleep time per 24 hours was 6.85 hours for residents in flexible programs and 7.03 for those in standard programs. Sleep duration and Karolinska Sleepiness Scale score were both noninferior in the flexible group versus the standard group, while noninferiority was not established between groups for alertness.

The iCOMPARE investigators wrote that the first trial “suggests that allowing program directors the discretion to make their own schedules without continuous duty-hour limits did not result in worse patient outcomes” and that the second trial indicates that intern sleep duration and sleepiness were noninferior in flexible versus standard programs, while results for alertness did not meet prespecified criteria for noninferiority. An accompanying editorial said that based on the results from these studies and previous research on duty hours, “We can confidently say that working flexible hours, still within the 80-hour constraints, does not result in higher patient mortality than working standard hours.” In addition, the trial shows that interns don't seem to get more or less sleep with either type of schedule, the editorialists said.

The editorialists also noted that the patient voice has been “conspicuously absent” in duty-hour research and that the effect on patients of duty-hour changes and other changes in health care delivery, such as hospitalist care and the implementation of electronic health records, is worthy of further attention. “This cultural shift is certainly not attributable to work-hour restrictions alone,” the editorialists wrote. “But as we move beyond the question of how many consecutive hours our most junior doctors can safely work, we will continue to ask how we might design a system capable of fostering the morale of its workforce, while simultaneously sustaining the relationships that remain fundamental to the well-being of both patients and their doctors.”