Is it dangerous to be admitted to an ICU during a weekend?

EJRC ARTICLE REVIEW

A number of studies have examined associations between ICU weekend admission and mortality and the results have been mixed. One of the reasons for this is the different case mix between weekdays and weekends. Therefore the authors of the present study wanted to add high-quality data to the field with the primary aim to examine associations between ICU admission/ICU stay at weekends with ICU mortality and ICU discharge.

Methods

This study was based on retrospective data from all adult patients admitted to 119 Austrian ICUs between January 2012 and December 2015. A total of 151,268 patients were included in the analyses, which were conducted using a proportinal subdistribution hazards model.

The case mix of patients admitted to ICUs on weekends differed from admission on weekdays as patients refereed to the ICU at weekends were sicker (median SAPS3 48; IQR 37-61) than patients admitted during the week (median SAPS3 42; IQR 33-54)

After adjustment for the different case-mix, patients admitted to the ICU on weekends still had a significantly increased risk of dying in the ICU. The adjusted sub distribution HRs (95% CI) for ICU mortality were 1.15 (1.08-1.23) and 1.11 (1.03-1.18), respectively, for patients admitted to an ICU on Saturday or Sunday compared with Wednesday.

Results

Chances of ICI discharge during weekends were significantly lower on Saturdays (HR 0.63 (0.62-0.64)) and Sundays (HR 0.56 (0.55-0.57)) compared to Wednesdays. This was also the case for the risk of dying in the weekend with hazard ratios of 0.93 (0.87-1.00) for Saturday and 0.85 (0.80-0.91) for Sunday compared to Wednesday.

Patients admitted to ICUs at weekends were less likely to receive several key treatments such as central venous catheters, peripheral arterial lines and lung function-improving treatment on the day of admission.

The study demonstrated that there are weekend effects on both ICU mortality and ICU discharge. Even though patients were at lower risk of dying in the weekend, patients admitted to the ICU during weekends had a significantly higher ICU mortality. Inadequate staffing and increased workload were suggested as possible explanations for worse outcomes for patients admitted at weekends.

Strengths & Limitations

Strengths of the study include the large number of patients and comprehensive statistical analyses and sub analyses to adjust for case-mix and other risk factors for death in the ICU. The main limitations include the retrospective design, which could induce information bias and possible limitations in the case-mix adjusting model.

Take Home Message

The study indicates that one of the reasons for increased ICU mortality for patients admitted during the weekend is a lower quality of care being provided during the weekend. ICUs need to make sure that equipment, expertise, and staff need to be available in the same quantity and quality on every day of the week.

This article review was submitted by Associate Professor Hanne Irene Jensen, member of the ESICM Ethics Section and the Journal Review Club.

References

1. 1. Zajic et al. Weekends affect mortality risk and chance of discharge in critically ill patients: a retrospective study in the Austrian registry for intensive care. Critical Care 2017:21.