Don’t worry doctors/don’t worry people – “July effect” or “Killing season” has no affect on most people


Main Point:

Researchers have found that “July effect” has nothing to do with mortality of low risk heart patients in teaching hospital.

Published in:


Study Further:

New medical graduate (Copyright ReSurge International, effect:

July effect is found to be an increased risk of medical errors and surgical complications that may result in mortality. It is the time of year, when new medical school graduates start working and the others in the wards are promoted.

It is the same time known as “Killing season” in United Kingdom.

Present Study:

In the present study, researchers worked on U.S. patients hospitalized for a heart attack in either May or July in 2002 to 2008. They found that although July effect is present but the worse outcomes of physician inexperience are only for the sickest patients of heart attack because of their age and other related factors of disease.

Researchers found that the sickest patients, who have high risk of mortality, died more in July, i.e. about 23%, than in May, i.e. about 19%, in highly teaching focus hospitals, whereas the proportion of patients who died in May and July was similar at less teaching focus hospitals, i.e. within 22% – 23%. On the other hand, the patients, who have low risk of mortality, have the same chances of dying in May and July in both the highly teaching focus hospitals as well as in less teaching focus hospitals.

“If this (July effect) phenomenon really exists, this study says it’s only limited to the sickest patients,” Rosenthal, from the University of Iowa Hospitals and Clinics in Iowa City, told Reuters Health.

“High risk AMI (acute myocardial infarction – heart problem) patients experience similar mortality in teaching- and non-teaching-intensive hospitals in July, but lower mortality in teaching-intensive hospitals in May. Low risk patients experience no such “July effect” in teaching-intensive hospitals,” Researchers concluded.

Moreover, when the researchers worked for all the 12 months of the year, they found that the patients fared better overall in teaching intensive hospitals and have a lower chances of death in those hospitals.


Anupam B. Jena et al. (2013). Mortality among High Risk Patients with Acute Myocardial Infarction Admitted to U.S. Teaching-Intensive Hospitals in July: A Retrospective Observational Study Circulation DOI: 10.1161/CIRCULATIONAHA.113.004074

Usman Zafar Paracha

Usman Zafar Paracha is a sort of entrepreneur. He is the author of "Color Atlas of Statistics", and the owner of an Android game "Faily Rocket."