Author + information
- Mahdi Khoshchehreh, MD, MS,
- Nasim Mirnateghi, PhD and
- Shaista Malik, MD, PhD∗ ()
- ↵∗Division of Cardiology, Department of Medicine, University of California Irvine Medical Center, 333 City Boulevard West, Suite 400, Orange, California 92868-3298
Kumar et al. (1) showed that patients admitted to the hospital with a principal diagnosis of acute myocardial infarction (AMI) during weekends have a significantly higher risk of in-hospital mortality than those admitted on weekdays. The authors suggest that delayed access to cardiac catheterization during weekends may explain this finding. We believe that few clarifications and alternative explanations are worth consideration.
As the authors pointed out, weekend admissions represent 26.1% of all admissions, instead of 28.5% (2 of 7 days of the week). Selection bias is a plausible explanation, as some patients with the least severe clinical symptoms may delay the diagnostic work-up and subsequently they would be admitted on the next working day, whereas patients with more severe symptoms are admitted the same day. Assuming this, the next working day should be associated with the highest number of admissions and probably the lowest death rate of the week.
The authors have performed an analysis of a large database to address an important question. The inability to distinguish between ST-segment elevation myocardial infarction (STEMI) and non–ST-segment elevation myocardial infarction (NSTEMI) is a major limitation of this analysis. There is a need throughout the paper to distinguish between STEMI and NSTEMI. The different approaches to manage STEMI (90 min door-to-balloon) and NSTEMI (early invasive in first 48 h or conservative management are recommended options) may have an impact on mortality. The more conservative approach for NSTEMI management allows for deferring more invasive interventions to next working day, and imaginably increases the risk of in-hospital mortality; however, this is not the case for STEMI.
We have widely explored the possible existence of a “weekend effect” and confirmed an increased risk of death for other acute cardiovascular diseases as well (2,3). Our findings using the same dataset showed higher mortality among NSTEMI patients only (3). Moreover, another study showed that although there were fewer patients with acute coronary syndrome (ACS) admitted than expected on nights and weekends, the proportion of patients with ACS presenting with STEMI was almost 65% higher on weekends (4). Could the authors provide this information?
The increased mortality rate reported by Kumar et al. (1) among weekend admitted patients for AMI may denote real excess deaths. But more substantial arguments are needed to rule out a mere selection bias. Also it must be noted that without precise information regarding the type of AMI and information on other cardiac interventions, the timing of cardiac catheterization cannot be viewed as a reliable indicator of the quality of care in patients with AMI.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation
- Kumar G.,
- Deshmukh A.,
- Sakhuja A.,
- et al.
- Khoshchehreh M.,
- Groves E.,
- Tehrani D.M.,
- Malik S.