Urban Myth or Reality?

Can patient safety be impacted by which day of the week or which month of the year one seeks medical treatment? This question has many in health care pondering whether these two effects, Weekend Effect and July Effect, are urban myth or reality. In July, both phenomena are relevant.

Weekend Effect

Recently, a study published in BMJ Quality & Safety examined the risk of death for patients admitted to hospitals on the weekend as opposed to weekdays.1 The researchers calculated 30-day in-hospital mortality rates for weekend versus Monday admissions for emergency or non-emergency surgeries from 28 metropolitan teaching hospitals. The dataset included 2,982,570 admissions between 2009 and 2012 from England, U.S., Australia, and Netherlands.

Except Australia, there was a higher risk of death for emergency admissions on the weekends in the other countries. The risk of death was:

  • 20% higher in Netherlands (six hospitals)
  • 13% higher in in the U.S (five hospitals)
  • 8% higher in England (11 hospitals)

In all four countries, there was a greater than two-fold higher risk of death for elective surgeries on Sundays compared to Mondays.1 Even though these results are based on a limited number of participating hospitals, their heterogeneous and multi-national nature suggests that this is an important phenomenon affecting medical institutions across borders.

Within the U.S., another study in the non-elective setting reported a significant Weekend Effect with 10.5% higher mortality on weekends compared with weekdays2 while a veteran affairs study for non-emergency surgical procedures revealed 17% higher adjusted odds of death for patients admitted postoperatively to hospital on Fridays compared with a Monday-to-Wednesday admission.3

These results corroborate previous studies showing a Weekend Effect for emergency and elective admissions even after adjusting for possible confounders.4,5,6 According to Professor Richard Lilford and Dr. Yen-Fu Chen of Warwick Medical School, “Understanding the weekend effect is an extremely important task since it is large at about 10 percent in relative risk terms and 0.4% in percentage point terms,” they write.“ This amounts to about 160 additional deaths in a hospital with 40,000 discharges per year.”7

In spite of this mounting evidence, controversy still exists as to the causes of the Weekend Effect. Unconfirmed factors include understaffing on weekends, inadequate numbers of experienced doctors on Fridays/weekends, different patient case-mix over weekends compared with weekdays and reduced availability of testing facilities.2

July Effect

July ushers in thousands of first-year residents to start their careers. According to the National Resident Matching Program, 30,035 positions were filled this year.8 In Great Britain, residents traditionally start in August which has notoriously been nicknamed “the August killing season”.9

One study examined all official U.S. computerized death certificates nationwide (n = 62,338,584) from 1979 to 2006 focusing on fatal medication errors–an indicator of critical medical mistakes–to test the “New Resident Hypothesis.”10 The study looked at mortality inside medical settings – inpatients, outpatients, and emergency departments. It was found that unlike any other month, fatal medication errors spiked in July by 10% above the expected level.

It is important to note that this July spike appeared only in teaching hospitals. Moreover, this uptick in mortality was seen only for medication errors and not for other causes of death or for deaths outside medical institutions.

With patient safety an increasing priority in recent years, teaching hospitals have made major changes to include more safeguards for residents. These safeguards include new evaluations standards and more attention to fatigue by capping work hours.

Do you think the Weekend Effect and July Effect are urban myth or reality?