Dying on the Weekend? Not So Fast, Say Two Studies Examining Hospital Care on Saturdays, Sundays

There is still much to be learned about why the so-called “weekend effect”—a phenomenon in which outcomes or quality of care suffer among patients admitted on Saturday or Sunday relative to the rest of the week—occurs and what can be done to address it, according to two new British studies.

The first study, by Cassie Aldridge, PhD (University of Birmingham, England), and colleagues, showed that in-hospital mortality was indeed higher among patients admitted as emergencies on the weekend, but the differences in the degree of involvement by specialist physicians did not explain the disparity.

And the second study—this one confined to acute stroke admissions—demonstrated that the weekend effect was just one of several variable patterns of quality of care and outcomes observed over the course of a week.

Both studies, which were published online May 10, 2016, ahead of print in the Lancet, highlight the uncertainty that remains regarding the weekend effect.

“Despite many claims about the quality of care [on] weekends and strong beliefs about the reasons for this, we need to remain open to the true extent and nature of any such deficit and to the possible causes,” Nick Black, MD (London School of Hygiene & Tropical Medicine, England), writes in an accompanying editorial. “Jumping to policy conclusions without a clear diagnosis of the problem should be avoided because the wrong decision might be detrimental to patient confidence, staff morale, and outcomes.”

Is Staffing the Problem?

Weekend hospital admission has been associated in some—but not all—studies with higher mortality rates for several conditions, with researchers pointing to suboptimal staffing levels for physicians and nurses, differences in case mix, and restrictions in access to diagnostic services as potential reasons for the finding.

But those explanations are speculative, and there is no definitive evidence establishing a causal link between any of those factors and poorer outcomes or quality of care on the weekends.

To explore the potential contribution of staffing levels for hospital specialists, Aldridge and colleagues performed a cross-sectional study that was part of the High-intensity Specialist Led Acute Care (HiSLAC) project. They distributed a survey to hospital specialists asking about the care of patients admitted as emergencies on 2 days in June 2014, a Sunday and a Wednesday; 15,537 clinicians from 115 acute hospital trusts across England’s National Health Service responded.

Only 11% reported providing care on Sunday, whereas 42% said they dealt with emergency patients on Wednesday. The average number of hours specialists spent handling emergencies was greater on Sunday (5.74 vs 3.97 hours), although specialist intensity—defined as the number of hours spent per 10 emergency admissions—on Sunday was roughly half that seen on Wednesday.

Looking at data for the entire fiscal year, in-hospital mortality was higher among patients admitted on the weekend compared with those admitted during the week (adjusted OR 1.10; 95% CI 1.08-1.11). However, there was no relationship between specialist intensity and the difference in mortality from weekend to weekday.

“The absence of an association in this preliminary cross-sectional study does not mean that we can discard the hypothesis that the weekend effect is attributable to insufficient presence of specialists, but it does require confirmation from the HiSLAC longitudinal study (phase 2) of concurrent secular changes in intensity and mortality,” the authors write. “Caution must be exercised in attributing the weekend effect to a single component in a complex system.”

Problems Found During the Week, Too

In the second study, Benjamin Bray, MD (University College London, England), and colleagues examined variation in the quality of acute stroke care according to both day and time over the course of a week. They analyzed data from the Sentinel Stroke National Audit Program on 74,307 patients admitted with acute stroke (ischemic or primary intracerebral hemorrhage) to 199 hospitals in England and Wales between April 2013 and March 2014.

Quality of care assessed with 13 indicators varied widely across the entire week—not just between the weekend and weekdays—with different patterns observed across measures.

“This finding suggests that even within a single, well-defined clinical pathway such as acute stroke care, temporal variation is a complex occurrence that probably has various causes,” the authors write.

Four main patterns of variation emerged:

• Diurnal, with quality varying based on the time of day 
• Day of the week, with quality varying across days of the week such that quality was lower on the weekend for certain measures (assessment by a stroke physician or nurse within 24 hours) and on Thursdays or Fridays for others (assessments by physiotherapy, occupational therapy, or a sleep and language therapist within 72 hours) 
• Off-hours, with poorer quality either overnight or on the weekend (particularly for a door-to-needle time of less than 60 minutes) 
• Flow pattern, with quality improving sequentially across weekdays and then deteriorating on the weekend 

The researchers found that 30-day survival did not differ when comparing daytime weekend admissions and patients admitted during the daytime weekdays (adjusted OR 1.03; 95% CI 0.95-1.13). Patients admitted overnight during the week, however, were less likely to survive (adjusted OR 0.90; 95% CI 0.82-0.99). Overnight admission on the weekend was also associated with lower survival in some statistical models.

“These findings imply that in acute stroke care, the weekend effect is a simplification of the true extent of temporal variation in healthcare quality that occurs across the week,” the authors say. “A focus only on reducing differences in care quality between weekends and weekdays will therefore not fully address the problem of variation in healthcare quality across the week.”

Caution Warranted

In his editorial, Black highlights the lessons to be learned from these new studies.

“First, caution should be taken in estimating the effect on mortality,” he says, pointing to limitations both of studies using administrative data and of studies using information from clinical databases for specific diseases or departments. “Although more such studies are needed to identify which patients might be at risk of weekend admission,” Black says, “what is really needed is a study in which accurate measures of severity are available on all admissions, so that meaningful comparisons of weekends and weekdays for the whole hospital can be made.”

The second conclusion that can be drawn is that greater attention should be placed on measures of quality of care aside from mortality—which is not particularly sensitive,” he says. Those might include quality of life, falls, hospital-acquired infections, delays in diagnosis and discharge, and extended lengths of stay.

And finally, “perhaps the wrong determinants of poor outcome are being investigated,” Black writes. “Maybe nurse staffing levels or the availability of diagnostic staff should be assessed rather than medical staffing. Or perhaps combinations of different professions. But even that approach might not be sufficient because research on inputs, such as staffing levels, risks missing the processes of care, known to be the key determinants of poor quality care.”

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