Do residents need more sleep? Two new studies in the New England Journal of Medicine compare the effects of standard versus flexible duty-hours on residents’ sleep and patient safety.

The iCOMPARE trial randomized 63 internal medicine residency programs, consisting of over 5,000 trainees, to standard duty-hour policies or flexible policies. All programs were held to an 80-hour work week, but flexible policies had no limits on shift lengths and did not mandate time off between shifts.

The first study compared sleep, sleepiness, and alertness among trainees in the two program types. While interns in the standard program got slightly more sleep per night, this did not differ substantially from those in the flexible programs. Interns in the flexible programs slept over an hour less on call, but caught up on sleep during non-duty days. Sleepiness also did not differ between the groups. Alertness was decreased for all interns during and after extended shifts, but was potentially worse among flexible-shift interns.

In the second study, the authors found that 30-day mortality, 7-day rehospitalizations, or Medicare payments in flexible programs did not differ substantially from those in standard programs. However, flexible programs were potentially worse with regards to prolonged hospital stays and 30-day rehospitalization rates.

My take home message: Overall, flexible shifts are not worse than standard shifts with regards to patient safety, and allowing internal medicine program directors to design their schedules without continuous duty-hour limits did not result in worse patient outcomes. However, long shifts in both programs were associated with fatigue and decreased alertness among residents.

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Judith Long, MD, is Chief of the Division of General Internal Medicine and an LDI Senior Fellow.

Study authors include LDI Senior Fellows David Asch, Jeffrey Silber, Judy Shea, and Kevin Volpp.