Patient Mortality Unaffected By Off-Hour Admission

PARIS—Patients admitted to ICUs during the “off” hours, such as nights, weekends, and holidays, when staffing levels tend to be lower, are not necessarily at a higher risk for mortality. Charles-Edouard Luyt, MD, PhD, and colleagues reported in the January issue of Critical Care Medicine that in-hospital mortality was slightly lower for patients admitted to ICUs during off-hour shifts than for those admitted during weekday day shifts.¹

The researchers examined data on more than 51,000 admissions to 23 ICUs over three years, with nearly two thirds of patients admitted during off-hours. They reported that staffing of the ICUs during day shifts consisted of a median of three intensivists, one intensivist-in-training, and two medical residents, while off-hour ICU staffing usually consisted of one intensivist on-site, sometimes with an accompanying medical resident. Overall, the hospital mortality rate was 22% and the ICU mortality rate was 17.7%.

Compared with off-hour admissions, patients admitted during day shifts were older, had greater disease severity (as measured by the Simplified Acute Physiology Score II [SAPS II]), had more failed organs, and more frequently required supportive measures. Day-shift admission patients also had longer mean lengths of stay in the ICU (8.1 days) and in the hospital (22.2 days), compared with those admitted off-hour (mean, seven days in the ICU and 18 days in the hospital). Transfer admissions were also more frequent during day shifts.

Off-hour admission patients had lower unadjusted mortality in the ICU (16.8%) and in the hospital (20.7%) than those admitted during weekday day shifts (19.4% and 24.5%, respectively), which “reflects their less severe disease,” stated the authors. But when Dr. Luyt and colleagues adjusted all mortality rates for age, sex, comorbidities, SAPS II, type of admission (ie, direct versus transfer), admission category, reason for admission, number of failed organs, supportive measures required, presence or absence of residents, and time of admission, they found that off-hour–admitted patients still had a slightly lower risk for death: Compared with weekday day-shift admissions, their odds ratio for in-hospital mortality was 0.93.

Further division into quartiles among patients by SAPS II and initial diagnosis still did not show increased in-hospital mortality among off-hour admissions, reported the researchers. Only the most critically ill patients (quartile 4) and those diagnosed with ischemic stroke who were admitted off-hour had significantly lower in-hospital mortality (adjusted odds ratios, 0.91 and 0.72, respectively).

Eddy Fan, MD, from the University of Toronto, and Dale M. Needham, MD, PhD, of Johns Hopkins University, stated in an accompanying editorial that the results of Dr. Luyt and colleagues initially might be surprising, as previous studies have found that lower ICU staffing levels are associated with worse outcomes.² While they acknowledged explanations for the possible confounding of results, they also allowed that the staffing scheme observed in the French ICUs might be on-target.

“The presence of an on-site intensivist … during off hours likely had an important impact on off-hours care of critically ill patients,” they said, citing recent studies that demonstrated the important impact of specialized ICU practitioners on mortality prevention. They expressed the need for solutions to the intensivist shortage in the United States “to provide patients with the best possible clinical care.”

—Jessica Dziedzic

Reference
1. Luyt C-E, Combes A, Aegerter P, et al. Mortality among patients admitted to intensive care units during weekday day shifts compared with “off” hours. Crit Care Med. 2007;35:3-11.
2. Fan E, Needham DM. An intensivist all day, keeps the bad outcomes away. Crit Care Med. 2007;35:286-287.

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