Weekend vs. Weekday Admission Carries No Added Risk for NSTE ACS Patients

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Patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS) experience longer delays to catheterization but do not have increased 30-day or 1-year mortality rates regardless of whether they present on the weekend or a weekday. The findings, from a large Canadian registry study, were published online October 16, 2013, ahead of print in the European Heart Journal: Acute Cardiovascular Care.

Michelle M. Graham, MD, of the University of Alberta (Edmonton, Canada), and colleagues gathered data from the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) registry on all 11,981 NSTE ACS patients admitted between April 1, 2005, and October 31, 2010, in southern Alberta. The region, which had a population of 3.5 million in 2010, is served by a single catheterization center.

Despite Longer Delays, No Added Mortality

Approximately one-third of admissions took place on weekends (32.1%) and the rest (67.9%) on weekdays. Baseline characteristics between the 2 groups were largely similar, though weekday admission patients were slightly more likely to have hypertension and to present at the intervention center.

Time from presentation to cardiac catheterization was higher in the weekend group, while the proportion of patients who were catheterized within 24 hours of admission was lower. Despite this, both 30-day and 1-year mortality rates were equivalent regardless of whether patients presented on a weekday or a weekend (table 1).

Table 1. Results According to Time of Presentation

After adjustment for baseline risk factors, weekend admission still did not significantly increase the risk of mortality at either 30 days (HR 1.06; 95% CI 0.82-1.38) or 1 year (HR 1.09; 95% CI 0.93-1.27)

Results Reassuring, Support Regionalized Care 

In an e-mail communication with TCTMD, Dr. Graham commented that the researchers had expected to find a difference in outcomes between weekend vs. weekday presentation based on prior studies that have shown increased mortality with weekend presentation for MI, “but we performed this study to obtain an objective analysis of cath times and outcomes and were very reassured by our results.”

Dr. Graham reported that the “findings could be generalizable to any large geographic area with well-developed referral and transfer processes in place, and a high-volume center providing invasive care.” Alberta’s health care system is not unique, she added, noting that the study “supports the concept that high-volume regionalized cath centers can provide excellent care, even for geographically disparate regions.”

An area for improvement would be speeding up transfer times for patients admitted to more rural centers, Dr. Graham suggested. “In addition,” she said, “we are doing further work exploring whether there remains a risk-treatment paradox whereby the highest risk patients are not receiving invasive investigation.”

Design Dilutes Ability to Detect Differences

But Hani Jneid, MD, of Massachusetts General Hospital (Boston, MA), expressed some skepticism about the results, not only regarding the optimistic interpretation that weekend patients are faring just as well as weekday patients, but also about the generalizability to other health care systems.

“My criticisms of the study are many,” he told TCTMD in a telephone interview. “It is surprising that the difference in time to catheterization between weekend and weekdays is very modest at less than 5 hours. Because of this modest difference, the likelihood of detecting a difference in mortality is very small. What was most surprising is that the delay is really large in both cohorts.”

The delays stem from the fact that Alberta is a public health system with only 1 center to serve not only a large geographic area but also a large population, Dr. Jneid added.

“Also, they diluted their ability to detect an effect by only examining weekends vs. weekdays,” rather than on- vs. off-hours, he commented. The latter category takes into account nighttime and holiday presentations.

Moreover, Dr. Jneid asserted that subgroup analysis based on TIMI risk score (approximately 30% of the study population had scores ≥ 4) might have revealed discrepancies, in which longer treatment delays would translate to increased mortality among the highest-risk patients.

 

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Source:
O’Neill DE, Southern DA, O’Neill BJ, et al. Weekend compared with weekday presentation does not affect outcomes of patients presenting with non-ST elevation acute coronary syndrome. Eur Heart J: Acute Cardiovasc Care. 2013;Epub ahead of print.

 

 

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