June 18 (HealthDay News) -- Extended work shifts pose a threat to the health and safety of medical interns and the patients they treat, according to a U.S. study of more than 2,700 interns.

The interns took part in a nationwide Internet survey and completed more than 17,000 monthly reports.

Study author Laura Barger of Brigham and Women's Hospital in Boston analyzed the data to determine the association between extended duration shifts (24 hours or more at a time), reported medical errors, and the interns' self-reported levels of stress.

Compared to months where no extended duration shifts were worked, interns who worked five or more extended duration shifts in a month were seven times more likely to report at least one fatigue-related significant medical error that harmed a patient, and 300 percent more likely to report fatigue-related errors that caused the death of a patient.

Interns who reported a medical error that caused harm to a patient were more than three times as likely to report high stress in that month, the study found.

"These results suggest that extended duration shifts negatively impact patient safety and the well-being of medical interns. (The findings) have important public policy implications for post-graduate medical education and suggest the need for counseling or other care for interns who make medical errors," Barger noted.

The study was presented Wednesday in Minneapolis at SLEEP 2007, the annual meeting of the Associated Professional Sleep Societies.

SOURCE: American Academy of Sleep Medicine, news release, June 13, 2007