Medical Reasons for 'Weekend Effect' Elusive

Two recent studies have bolstered the argument that the so-called "weekend effect" exists. Like earlier studies, however, neither new study can say exactly why it's happening.

A Johns Hopkins study published this month in the Journal of Surgical Research reviewed more than 38,000 patient records of older adults who sustained head trauma over the weekend and found that they were 14% more likely to die from those injuries than patients with similar injuries who were hospitalized Monday through Friday, even after accounting for other factors.

"The underlying mechanism responsible for this disparity may be related to differences in weekday versus weekend staffing," the study concluded. "However, this must be studied further so that the factors driving disparities in outcomes can be thoroughly understood and the increased risk associated with weekend treatment for head trauma can be eliminated."

The study's lead author, Eric B. Schneider, an epidemiologist at the Johns Hopkins University School of Medicine's Center for Surgical Trials and Outcomes Research, said "there isn't a medical reason for worse results on weekends."

"It's more likely a difference in how hospitals operate over the weekend as opposed to during the week, meaning that there may be a real opportunity for hospitals to change how they operate and save lives," Schneider said in prepared remarks.

A separate study published last month in the Archives of Surgeryreviewed 31,832 patient files and found worse outcomes for patients undergoing urgent surgery for left-sided diverticulitis who were admitted on the weekend versus weekdays.

"Patients undergoing urgent surgery for left-sided diverticulitis who are admitted on a weekend have a higher risk for undergoing a Hartmann procedure and worse short-term outcomes compared with patients who are admitted on a weekday," the study concluded. "Further research is warranted to investigate possible underlying mechanisms and to develop strategies for reducing this substantial weekend effect."

Previous studies have documented the weekend effect for heart attack, stroke, and aneurism, but none say precisely what is driving the phenomenon.

A March 2010 study from the federal Agency for Healthcare Research and Quality found that patients admitted to a hospital on a weekend are half as likely to get procedures they need on the same day they arrive than if they were admitted on a weekday. That study also found that 2.4% of patients admitted on the weekend died in the hospital, compared to 1.8% of patients admitted during the week.

The AHRQ study did not draw any conclusions from the data about the quality of care provided on weekends versus weekdays in the nation's hospitals because the results were not adjusted for severity of illness. "This report does raise the issue that there could be a 'weekend' effect, but that further study is needed," lead author P. Hannah Davis said at the time. "We can't conclude that there is a weekend effect."

Robert O'Connor, MD, chair of emergency medicine at the University of Virginia and a board member of the American College of Emergency Physicians, told HealthLeaders Media "it's hard to say" whether the weekend effect is real.

"Do I think it exists? It has been reported in a number of disease states from data registries and we need to find out if this is real or not," he says.

"A lot of these studies are retrospective looking at databases that weren't designed to collect data prospectively. While I am very concerned about what they might be showing, I'd be very worried that if there is a difference it is something we would need to identify and correct as a healthcare system."

While lower staffing levels on the weekends might be an obvious hindrance for many medical services, O'Connor says many emergency departments maintain consistent staffing levels throughout the week. He says the findings in the Johns Hopkins study might be more dependent upon how the data was measured.

"I'd like to see it broken down by trauma center, either level one, two or three. I would like to see more data collected on the patients to make sure that they absolutely are comparable in terms of their Glasgow Coma Scale and other injuries," he says.

"The authors did a nice job with the retrospective database but we would have to collect the data prospectively, that is look at whether the patient came in on the weekend or the weekday and make sure as much data is collected from both groups to help sort out this problem."

O'Connor says arguments about the existence or extent of the weekend effect will remain until better data shows whether or not it's real. "The reason it is still a question is that this has been reported for a variety of other conditions such as aneurisms, strokes, and cardio vascular emergencies. But they have all been from retrospective databases. There are also a number of studies to the contrary that point out no difference," he says. "The reason this issues still sticks around is that we are trying as a profession to get a handle on whether this is real or not."