'July Effect' is a Fallacy, New Study Shows

New research debunks the notion that July suffers more medical errors than any other month owing to an influx of new medical school grads starting their hospital training.

The "July Effect" is a fiction.

According to the lore surrounding the medical myth, July suffers more medical errors than any other month because of an influx of new medical school graduates starting their hospital training.

Not so, according to new research published this month in The Annals of Thoracic Surgery.

Researchers from Brigham and Women’s Hospital in Boston tapped the Nationwide Inpatient Sample and looked at more than 470,000 cardiac procedures such as coronary artery bypass grafting, aortic valve replacement, mitral valve repair or replacement, and thoracic aortic aneurysm replacement performed between 2012 and 2014 on adult patients.

For each procedure, overall trends were compared by academic year quartiles: Q1 (July to September with the least experienced residents) vs. Q4 (April to June with the most experienced residents), the study said.

The researchers observed no differences in mortality, in-hospital complications, costs, or length of stay between patients who were treated in Q1 compared to those in Q4, the study said.

Study author Sameer A. Hirji, MD, called the findings "encouraging."

"While the perception of the 'July effect' persists culturally among healthcare providers, we hope that this study reinforces the fact that hospital systems have in place processes that help provide the highest level of care and ensure patient safety,” Hirji said.

Study co-author Rohan M. Shah, MD, said the findings make sense because "cardiac surgery patients are managed in a multidisciplinary fashion."

"Therefore, the well-being of patients is not solely dependent on one individual, but rather on the entire caregiving team and so may be more resistant to changes in hospital staff," Shah said. "What this means for patients is that they should not be fearful or concerned about having surgery in July when the new residents are starting."

Hirji said that most cardiac surgery teams adopt "direct and strict" supervision of newly arriving trainees, with increased resident autonomy given as the year progresses.  

"The balance between attending supervision and resident autonomy constantly shifts during teaching," he said. "This is a fine balance and, as indicated by this study, our specialty is doing a great job."