The effects of reduced residency work hours on patient safety as well as trainee well-being and education have been the subject of much controversy. But new results from the iCOMPARE trial may finally bring the debate to an end.

The trial shows that with regard to several measures of patient safety, including patient death, programs with flexible resident hours are no worse than programs with standard hours. Resident well-being, including factors such as chronic sleep loss and excessive sleepiness, is likewise similar for these programs.

Editorialists Lisa Rosenbaum, MD, and Daniela Lamas, MD, both of Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, say that the issue of duty hours can now, in many ways, be laid to rest.

"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," they write in an editorial accompanying two studies, which were published online today in the New England Journal of Medicine.

"We also now know that interns do not sleep significantly more or less when following either of these schedules," they continue.

Although more study may not be what's called for, not all issues have been addressed, according to the editorialists. Most notably, studies have left out the experience of patients. In some cases, patients may not even know the name of their physicians because of frequent changes in shift.

"[A]s 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," Rosenbaum and Lamas emphasize.

ACGME Restrictions Prompted Years-Long Debate

The debate has been going on at least since 2003, when the Accreditation Council of Graduate Medical Education (ACGME) limited resident work hours to 30-hour shifts and 80-hour work weeks, with at least 1 day off every 7 days, and caps on the frequency of overnight calls. The council subsequently enabled programs to obtain waivers that allowed more flexibility on shift length and time off between shifts, while maintaining the 80-hour work week cap, limits on overnight calls, and mandatory days off.

Subsequently, studies have suggested that programs with standard resident hours and those with flexible resident hours are similar with respect to patient safety. As reported previously, a cluster-randomized trial of 117 general surgery residency programs showed no significant difference in rates of death or serious complications among flexible-hour vs standard-hour programs.

In addition, no difference was found in the quality of training between flexible-hour and standard-hour programs.

However, previously reported results from iCOMPARE, a cluster-randomized trial of 63 internal medicine residency programs, are less clearcut with respect to the effect on resident well-being. The results suggested no significant difference in time spent on patient care and in scores on in-training exams for flexible vs standard programs, but residents in flexible programs reported more dissatisfaction with regard to overall well-being and the quality of their education.

Now, the latest analyses from the iCOMPARE trial address issues of patient safety and resident sleep.

iCOMPARE Reveals Little Difference in Outcomes

The iCOMPARE trial took place from July 2015 through June 2016; 31 programs were assigned to employ standard work hours in accordance with the 2011 ACGME policies, and 32 programs were assigned to employ flexible work hours.

In the patient safety analysis, Jeffrey Silber, MD, PhD, from Children's Hospital of Philadelphia, Pennsylvania, and colleagues evaluated change in 30-day mortality and other patient safety outcomes. They compared outcomes from the year before to the year after randomization for flexible-shift vs standard-shift programs.

The analysis included 264,585 admissions during the 2-year study period. Researchers used Medicare claims data, which allowed for tracking death while hospitalized and after discharge.

The results show that change in 30-day mortality was no worse for the flexible-hour programs (12.6% in the pretrial year vs 12.5% in the trial year) compared to the standard-hour programs (12.7% in the pretrial year vs 12.2%). The results were significant for noninferiority and met a prespecified noninferiority margin of 1% (P = .03 for noninferiority).

Likewise, Medicare payments, patient safety indicators, and 7- and 30-day readmission rates were no worse for flexible-hour programs than for standard-hour programs.

Analyses that adjusted for age, sex, race/ethnicity, medical conditions, and type of admission yielded similar results.

Prolonged length of stay failed to meet noninferiority requirements.

In the report on resident sleep problems, Mathias Basner, MD, PhD, from the Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, and colleagues used objective measures to compare sleep duration and other variables related to acute and chronic sleep loss. The study included data obtained over 14 days from 205 interns at six flexible-hour programs and 193 interns at six standard-hour programs.

Results show that chronic sleep loss was no worse for residents in flexible-hour vs standard-hour programs (between-group difference in sleep duration, −0.17 hours per day; one-sided lower limit of the 95% confidence interval, −0.45 hours). The findings were significant for noninferiority and met the noninferiority margin of 0.5 hours (P = .02 for noninferiority).

Likewise, excessive sleepiness was no worse for flexible-hour vs standard-hour programs. Results were unchanged after adjusting for age and sex.

However, alertness failed to meet noninferiority requirements.

Residents in flexible-hour programs slept, on average, 6.85 hours per day, compared to 7.03 hours per day in standard programs.

Compared with interns in standard-hour programs, those in flexible-hour programs averaged 2.23 hours less sleep during night calls, but they made up for it by sleeping more hours on days off. After an extended night shift, interns in flexible programs reported less alertness and higher levels of excessive sleepiness than during day shifts.

The study was supported by grants from the National Heart, Lung, and Blood Institute and from the Accreditation Council for Graduate Medical Education. One or more authors report having received grants and/or personal fees from one or more of the following: Accreditation Council for Graduate Medical Education, National Heart, Lung, and Blood Institute, SEA Medical Systems, EarlySense, CDl (Negev), ValeraHealth, MDClone, Pulsar Informatics, Inc., and/or the NIH. Coauthor Sanjay Desai, MD, is a member of the Internal Medicine Review Committee for the ACGME. Rosenbaum is employed by Brigham and Women's Hospital, Harvard Medical School, and is a national correspondent for the NEJM. She was a Robert Wood Johnson Clinical Scholar at the University of Pennsylvania. Lamashas has disclosed no relevant financial relationships.

N Engl J Med. Published online March 6, 2019. Silber et al, Abstract; Basner et al, Abstract; Editorial

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