Elsevier

Journal of Critical Care

Volume 23, Issue 3, September 2008, Pages 317-324
Journal of Critical Care

Systems-Based Practice/Investigation
Hospital mortality among adults admitted to and discharged from intensive care on weekends and evenings

https://doi.org/10.1016/j.jcrc.2007.09.001Get rights and content

Abstract

Purpose

Patient care may be inconsistent during off hours. We sought to determine whether adults admitted to or discharged from intensive care units (ICUs) on evenings and weekends have increased mortality rates.

Materials and Methods

All adults admitted to ICUs in the Calgary Health Region, Alberta, Canada, during 2000 to 2006 were included. The in-hospital mortality risk was assessed with admissions or discharges on weekdays (Monday to Friday) and daytime (8:00 am to 5:59 pm) as compared with weekends (Saturday and Sunday) and nights (6:00 pm to 7:59 am).

Results

Intensive care unit admissions (n = 20 466) occurred during weekends in 18%, nights in 41%, and nights and/or weekends in 49%. Among the 17 864 survivors to ICU discharge, 26% were discharged on weekends, 21% at night, and 41% on nights and/or weekends. Increased crude mortality rates were associated with both admission (24% vs 14%, P < .0001) and discharge (12% vs 5%, P < .0001) during nights as compared with days. Admission to (26% vs 16%, P < .0001) but not discharge from (6% vs 7%, P = .42) ICU during weekends as compared with weekdays was associated with increased mortality. After controlling for confounding variables using logistic regression analyses, neither weekend admission nor discharge was associated with death. However, both night admission and discharge were independently associated with mortality.

Conclusions

Our observations of excess risk associated with admission to or discharge from ICU at night merits further exploration as to whether it may reflect inconsistencies in care after hours.

Introduction

Several studies conducted in a number of different populations indicate that patients admitted to hospitals on weekends and evenings have a higher mortality rate [1], [2], [3], [4], [5], [6], [7]. Many factors have been proposed to explain these observations including lower levels of staffing and restricted availability of tests and procedures during these times. In addition, patients admitted “after hours” may be intrinsically at higher risk for death by virtue of a different case mix or increased severity of illness as compared with patients admitted during usual business hours. As a result of their acuity and severity of illness, patients admitted to intensive care units (ICU) represent a distinct in-hospital population. Although the body of literature is limited, studies conducted in critically ill populations have largely demonstrated higher crude mortality rates associated with admission during weekends and evenings [8], [9], [10], [11], [12], [13], [14]. However, in many cases, no increased risk associated with off-hours admission was present after controlling for confounding factors [8], [10], [12], [13]. Similarly to off-hours admissions, weekend and evening discharge from ICU has also been associated with increased mortality risk [15], [16], [17].

If admission to or discharge from ICU after hours and/or on weekends truly increases the risk for an adverse outcome, then a major safety and process of care issue is present that requires attention. A relatively small number of studies have specifically looked at the effect of admission timing and outcome in adult ICUs, and even fewer have assessed the effect of timing of discharge. We undertook the present study to explore the effect that timing of admission to and discharge from ICU may have on mortality outcome.

Section snippets

Study population

The Calgary Health Region (CHR) provides virtually all acute hospital care to the residents of the cities of Calgary and Airdrie and a large surrounding area (population, 1.2 million) in the Province of Alberta, Canada. Critically ill adult patients in the CHR are managed in closed ICUs under the care of the Department of Critical Care Medicine, University of Calgary and CHR. These currently include a 14-bed cardiovascular surgery ICU (CVICU) and 3 multisystem ICUs: one 24-bed multisystem ICU

Results

During the 7-year study period, a total of 24 204 ICU admissions occurred among 20 466 adult patients. Sixty-four percent (13 119) of patients were male, the median age was 63.7 years (IQR, 49.9-73.8 years), and the mean ± SD APACHE II score was 25.1 ± 8.48 (n = 20 338). Intensive care unit admissions occurred during weekends (Saturday and Sunday) in 3715 (18%) cases, during the night (6:00 PM -7:59) in 8450 (41%), and on nights and/or weekends in 9987 (49%) cases. Among 17 864 survivors to ICU

Discussion

After controlling for a number of covariates, we found that, although there is no evidence of a “weekend effect,” patients admitted after hours are at increased risk for death. A number of investigators have observed increased risk for mortality associated with ICU admission on weekends, but this excess mortality has largely been explained by increased rates of admission of sicker patients or those with a different case mix [8], [9], [10], [11], [12], [13]. Although we adjusted for a number of

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  • Cited by (0)

    No external funding was received for this study. None of the authors have financial or professional conflicts of interest that would influence the conduct or reporting of this study.

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