New Brunswick, NJ - Patients with MI who come to the hospital on weekends are less likely to survive than patients who are admitted to the hospital during the week, a new study has shown [1]. Likely mediating this higher rate of mortality, say investigators, is the additional finding that admission on the weekend is associated with lower use of invasive cardiac procedures.

Publishing their findings in the March 15, 2007 issue of the New England Journal of Medicine, lead author Dr William Kostis (Robert Wood Johnson Medical School, Piscataway, NJ) and colleagues write that this higher rate of mortality represents 9 to 10 additional deaths per 1000 admissions per year and has important implications for clinical care.

"The increase in mortality, which may persist for more than a year, could account for several thousand deaths annually in the United States," write the authors. "More appropriate hospital staffing or regionalization of the care of patients with acute myocardial infarction may prevent some of these deaths."

In an editorial accompanying the published study, Drs Donald Redelmeier and Chaim Bell (University of Toronto, ON) note that while clinicians strive to provide care to patients every day of week, doing so is difficult, partly because many who work in hospitals are not always compensated for taking the weekend shift [2]. Even casual observations of the hospital parking lot on a Saturday suggest that the intensity of care on the weekend does not match the care provided on other days of the week, they write.

"The shortfall of weekend medical care is important because the consequences of adverse events cannot always be offset by working harder on subsequent days," write Redelmeier and Bell. "If the patient dies on the weekend, no heroics on Monday will suffice."

Kostis and colleagues note that hospital staffing is typically reduced on weekends, both in terms of the number of clinicians and the available expertise on site. While the difference in staffing might result in different outcomes for patients with acute conditions—management of acute MI, specifically, requires urgent diagnostic and therapeutic procedures—findings from previous studies have been inconsistent.

If the patient dies on the weekend, no heroics on Monday will suffice.

To compare mortality rates among patients admitted with MI on weekends and those admitted during the week, investigators obtained data from the Myocardial Infarction Data Acquisition System (MIDAS), a database that contains clinical data on patients discharged with an acute MI diagnosis from nonfederal hospitals in New Jersey as well as information on the use of invasive cardiac procedures such as catheterization, PCI, or CABG. The study included 231 164 patients admitted to New Jersey hospitals between 1987 and 2002 with acute MI as the primary reason for admission.

Overall, there were no significant differences in demographic characteristics, coexisting conditions, or infarction site between patients admitted on weekends and those admitted during the week. Despite this, patients admitted on the weekend were less likely to undergo invasive cardiac procedures, especially on the first and second days of hospitalization.

Mortality 30 days after admission was also significantly higher for patients admitted on a weekend than for those admitted during the week. This difference became significant the day after admission and persisted until one year. Mortality on the weekend remained significantly higher after adjustment for clinical characteristics, but became nonsignificant after the additional adjustment for invasive cardiac procedures, the investigators report.

Overall, our study suggests that a hospital workweek of Monday through Friday is not optimal for the care of patients with acute myocardial infarction.

When the analysis was restricted to admissions to hospitals equipped to perform PCI, the adjusted risk of death at 30 days was still increased for weekend admission, the authors report.

Kostis and colleagues point out that unmeasured confounders might have contributed to the reported differences in mortality between patients admitted on weekends and those admitted on weekdays. For example, the MIDAS database does not include data on the time from the onset of symptoms to presentation, infarct size, hemodynamic status at presentation, or medications administered during hospitalization. None of these limitations, they contend, "detract from the fact that mortality was higher and the rate of invasive procedures was lower for weekend admissions."

"Overall," the authors conclude, "our study suggests that a hospital workweek of Monday through Friday is not optimal for the care of patients with acute myocardial infarction."

In an audio supplement to the published study, Dr Thomas Lee (Partners Health Care System, Boston, MA), one of the associate editors of the journal, said that most hospitals would reduce overhead costs if labs could run full time, but staff shortages preclude hospitals from operating 24 hours per day, seven days per week [3]. While aware there are falloffs in how aggressive physicians are with patients having an MI on the weekend, Lee said he was surprised at how many fewer angioplasties were performed on the weekend.

A lot of times it doesn't make a difference if you wait and do those procedures on Monday, but myocardial infarction is one diagnosis where it does make a real difference.

"When people are not in the hospital, and they are further away, the threshold for calling somebody in is very different," commented Lee. "On the weekend, at night, waking up your colleagues, calling them, it's very inconvenient, and doctors will use a different threshold [for calling the cath lab team in]. The result is that fewer procedures are performed. A lot of times it doesn't make a difference if you wait and do those procedures on Monday, but myocardial infarction is one diagnosis where it does make a real difference."

According to editorialists Redelmeier and Bell, an awareness of the shortfalls in weekend hospital care has implications for patients. If patients feel unwell during the week, they should not wait until the weekend to see whether they feel better. Second, if unsure how sick they might be, they should contact their doctor before the end of workweek. And finally, if hit by a medical emergency on the weekend, they should still proceed to the emergency department, as they are still far safer there than at home.

To offset the disparity in weekend care, Lee said his hospital attempts to schedule physicians who live close to the hospital for on-call service. In addition, the emergency department is able to directly activate the cath lab team without having to first call a cardiologist.

"We run the risk that the cath lab team might come in and find that it wasn't a myocardial infarction at all, but we feel it's a small price to pay for reducing the delay," said Lee. If such solutions do not work, Lee said some hospitals might have very little choice but to pay to operate the cath lab at night and on weekends or else live with the notion that they are providing second-rate care.