A
Journal of General Internal Medicine study, published in 2010, investigated medical errors from 1979 to 2006 in United States hospitals and found that medication errors increased 10% during the month of July at
teaching hospitals, but not in neighboring hospitals. Surgical errors did not increase, leading to the hypothesis that medication errors are easier for new personnel to make because they are
prescribing drugs on their own, rather than being cross-checked by others. The study did not have sufficient data to link the increased errors to new residents, however, and further study would need to be done in order to determine the sources of this increase. A criticism of the study suggests that the supervision of new residents and the patient loads at teaching hospitals have improved since 1979 and that the results may be skewed by including much older data. Other studies searching for the July effect have found variable evidence of an increased risk, with several studies finding no risk at all. • A 2010 study published in the
Journal of Trauma found an increased risk of errors that resulted in preventable complications but these errors had no significant impact on
mortality. • A 2009 study published in the
Journal of the American College of Surgeons found no month-by-month differences in outcomes of
medical trauma patients. • A 2009 study published in the
Journal of Stroke and Cerebrovascular Diseases found no evidence of the July effect for patients with acute
ischemic stroke. • A 2009 study published in the
Southern Medical Journal found no difference in the medical management of patients with acute
cardiovascular conditions. • A 2008 study published in
The American Journal of Surgery found no seasonal difference in outcomes for
cardiac surgery patients. • A 2007 study published in the
Annals of Surgery found a significant seasonal variation with surgical outcomes, with an increase in postsurgical
morbidity and
mortality associated with the beginning of the academic year. • A 2006
Journal of Neurosurgery: Pediatrics study found a small increase in the risks associated with
cerebrospinal fluid shunt surgery in children during the months of July and August. • A 2003
Obstetrics & Gynecology study found no July effect in
obstetric procedures. • A 2011 systematic review in the
Annals of Internal Medicine found that during year-end changeovers, hospital mortality increases and hospital efficiency decreases. • A 2016 study in
JAMA Surgery found no evidence of the July effect in patient-experience outcomes in surgical patients. • A 2019 study from the Yale School of Medicine found no difference in morbidity or mortality after Whipple procedures (
pancreaticoduodenectomy) performed in July compared to the remainder of the academic year. ==United Kingdom==