July is the worst month to check into a teaching hospital, UCSD researchers say


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July is the worst month to check into a teaching hospital because of the influx of inexperienced residents, UC San Diego researchers reported Wednesday. The rate of fatal medical errors spikes in July, increasing by 10% compared with the average in other months, they reported in the Journal of General Internal Medicine. The increase occurred only in counties with teaching hospitals.

Many physicians have long suspected an increased rate of medical errors when new residents join hospitals, a phenomenon commonly referred to as the ‘July effect.’ But hard evidence supporting the possibility had been hard to come by, said social scientist David H. Phillips of UCSD, because most previous studies had examined small, non-geographically representative samples over a limited time period. Perhaps the best evidence to date was a five-year study of anesthesia trainees at an Australian hospital that showed an increase in errors in February, the first month of their academic year.


Phillips and graduate student Gwendolyn E. C. Barker studied all 62,338,584 U.S. death certificates for the period 1979 to 2006, ultimately focusing on 244,388 deaths linked to medication areas. They found an average increase of 10% in medication-linked deaths in July in counties with teaching hospitals but none in other counties. The proportion of such deaths was highest in those counties with the highest number of teaching hospitals. Studying deaths outside the hospital, they found no similar spike in deaths during the period, suggesting that it was not simply a summertime phenomenon. They found no spike in other causes of death in hospitals during July, however.

Their findings, they wrote, ‘provide fresh evidence for 1) re-evaluating responsibilities assigned to new residents; 2) increasing supervision of new residents; [and] 3) increasing education concerned with medication safety.’

-- Thomas H. Maugh II