The storied "July effect" that new residents and fellows have on patient outcomes in teaching hospitals is negligible in spinal surgery patients, researchers found.
A retrospective review of nearly 970,000 admissions over 8 years for spinal surgery showed little difference between mortality rates during July in teaching hospitals compared with other months (OR 0.94, 95% CI 0.78 to 1.11, P=0.46). But postoperative infections at teaching hospitals were significantly more likely to occur, according to findings by Jennifer S. McDonald, PhD, of the Mayo Clinic in Rochester, Minn., and colleagues.
"As these complications are wound-related and are often under the purview of residents and fellows, this higher likelihood in July suggests the presence of a learning curve," the authors wrote online in the Journal of Neurosurgery: Spine. However, they attributed the increased incidence to the large data size in the study, noting that "the magnitude of the difference was quite small."
The study looked at July because it is the month when new residents and fellows begin working at teaching hospitals. "This change in hospital staff has been postulated as a potential source of error that may result in worse patient outcomes in July," the authors noted in their introduction. Previous smaller studies of the "July effect" have fallen on both sides of the debate and lack definitive results, they wrote.
A 2011 systematic review of 39 "July effect" studies suggested, but could not conclude, that it exists. But "additional studies are therefore needed to determine whether patients are at an increased, significant risk of poor outcome in teaching hospitals during these transition months," the authors wrote.