What’s New in the Patient Safety World

November 2013

The Weekend Effect: Not One Simple Answer



The “weekend effect” is a term used to refer to an increase in untoward events or suboptimal outcomes occurring in patients admitted to hospitals over the weekend. In some cases we use the term “after hours effect” since some of the same issues occur in patients admitted at night. We’ve discussed the numerous factors that may contribute to the “weekend effect” in our previous columns listed at the end of today’s column.


Though few doubt the phenomenon exists, debate remains whether it reflects suboptimal medical care or simply that patients admitted on weekends tend to be sicker. Various studies have demonstrated higher mortality rates for patients admitted on weekends with strokes, atrial fibrillation, diverticulosis surgery, a variety of other surgical procedures, head trauma, COPD, CHF, perinatal events, ICU admissions, ESRD, and other conditions. In fact, in our June 2011 What’s New in the Patient Safety World “Another Study on Dangers of Weekend Admissions” we noted a study (Ricciardi 2011) that found that mortality rates were higher for 15 of 26 major diagnostic categories when patients were admitted on weekends. Even after adjustment for comorbidities and a variety of other clinical and demographic characteristics there remained a significant increase in mortality, on the order of 10% higher for those admitted on weekends.


Now a new study from Austrailia (Concha 2013) has used large linked databases to delve further into the issue. They analyzed over 3 million emergency department admissions over a 7-year period. 27% of all admissions came on weekends and such admissions accounted for 28% of all deaths at one week after admission. Sixteen of 430 diagnosis groups had a significantly raised mortality risk after weekend admission (and no DRG’s were associated with lower mortality for weekend admissions). But the timing of deaths was not uniform and several patterns were seen. One pattern was death within the first 24 hours, seen only in patients with the DRG for major arrhythmia and cardiac arrest. A second pattern of steady risk by day was seen primarily in patients with cancer. The most common pattern, however, was a “mixed” effect in which there was a spike in mortality over the weekend that reduced on exposure to weekday care but remained elevated thereafter. Their overall conclusion is that for most of the DRG’s showing excess mortality with weekend admission there are both patient-related factors and care-related factors in play.


Our healthcare systems clearly do not deliver uniform care 24x7. The differences between the hospital during weekday daytime hours and the hospital at night and on weekends is striking. Staffing patterns (both in terms of volume and experience) are the most obvious difference but there are many others as well. Many diagnostic tests are not as readily available during these times. Physician and consultant availability may be different and cross-coverage by physicians who lack detailed knowledge about individual patients is common. You also see more verbal orders, which of course are error-prone, at night and on weekends.


But often it is the difference in non-clinical staffing that is a root cause. Our December 15, 2009 Patient Safety Tip of the Week “The Weekend Effect” discussed how adding non-clinical administrative tasks to already overburdened nursing staff on weekends may be detrimental to patient care. Just do rounds on one of your med/surg floors or ICU’s on a weekend. You’ll see nurses answering phones all day long, causing interruptions in some attention-critical nursing activities. Calls from radiology and the lab that might go directly to physicians now go first to the nurse on the floor, who then has to try to track down the physician. They end up filing lab and radiology reports or faxing medication orders down to pharmacy, activities often done by clerical staff during daytime hours. Even in those facilities that have CPOE, nurses off-hours often end up entering those orders into the computer because the physicians are off-site and are phoning in verbal orders. You’ll also see nurses giving directions to the increased numbers of visitors typically seen on weekends. They even end up doing some housekeeping chores. All of these interruptions and distractions obviously interfere with nurses’ ability to attend to their clinically important tasks (see our Patient Safety Tips of the Week for August 25, 2009 “Interruptions, Distractions, Inattention…Oops!” and May 4, 2010 “More on the Impact of Interruptions”).


Maybe if hospitals were able to quantify the weekend effect in financial terms they might pay more attention to the root causes of the phenomenon. The weekend effect includes not just excess mortality but also morbidities and complications and also impaired throughput that leads to longer lengths of stay. These can all lead to excess costs.  One recent study (Gilmore 2013) showed that colectomies performed on Mondays were associated with significantly shorter lengths of stay than those performed any other day of the week. The authors attribute that to patients taking full advantage of hospital resources and ancillary support. Another recent review of obstetrical complications (Snowden 2013) showed that on weekends, relatively high-volume days were significantly associated with an elevated risk of infant asphyxia, whereas no association was present on weekdays. Cost of care of such infants is very expensive. Both are examples where providing adequate resources up front can save money on the back end.


The weekend effect is complex and involves both patient-related factors and quality of care factors. And it affects primarily a subset of the total hospital patient population. While there may be little we can do about the patient-related factors, certainly we can do a better job on the quality-related factors. Greater attention to providing adequate resources for patients with those conditions and DRG’s known to be impacted by the weekend effect should be a focus for all.





Some of our previous columns on the “weekend effect:







Ricciardi R, Roberts PL, Read TE, et al. Mortality Rate After Nonelective Hospital Admission. Arch Surg. 2011; 146(5): 545-551




Concha OP, Gallego B, Hillman K, et al. Do variations in hospital mortality patterns after weekend admission reflect reduced quality of care or different patient cohorts? A population-based study.  BMJ Qual Saf 2013; published online 25 October 2013 doi:10.1136/bmjqs-2013-002218




Gilmore DM, Curran T, Gautam S, Nagle D, et al. Timing is everything—colectomy performed on Monday decreases length of stay. Am J Surg 2013; 206(3): 340-345, September 2013




Snowden JM, Darney BG, Cheng YW, et al. Systems Factors in Obstetric Care: The Role of Daily Obstetric Volume. Obstetrics & Gynecology2013; 122(4): 851-857







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