Association Between Afterhours Discharge From the Intensive Care Unit and Hospital Mortality: A Multi-Center Retrospective Cohort Study.

BACKGROUND: There is conflicting evidence on the association between afterhours discharge from the intensive care unit (ICU) and hospital mortality. We examined the effects of afterhours discharge, including the potential effect of residual organ dysfunction, on hospital mortality in a large integrated health region. METHODS: We performed a multi-center retrospective cohort study of 10,463 adults discharged from 9 mixed medical/surgical ICUs in Alberta from June 2012 to December 2014. We applied a 2-stage modeling strategy to investigate the association between afterhours discharge (19:00h to 07:59h) and post-ICU hospital mortality. We applied mixed-effect multi-variable linear regression to assess the relationship between discharge organ dysfunction and afterhours discharge. We then applied mixed-effect multi-variable logistic regression to evaluate the direct, indirect and integrated associations of afterhours discharge on hospital mortality and hospitalization duration. RESULTS: Of 10,463 patients, 23.7% (n = 2,480) were discharged afterhours, of which 27.4% occurred on a holiday or weekend. This varied significantly by ICU size, type, and site. Patients discharged afterhours were more likely medical admissions, had greater multi-morbidity and illness acuity. A greater average SOFA score in the 72 hours prior to ICU discharge was not associated with afterhours discharge. However, a greater average SOFA score was associated with hospital mortality (adjusted-odds ratio [OR], 1.23; 95% CI, 1.18-1.28). Afterhours discharge was associated with higher hospital mortality (adjusted-OR, 1.19; 95% CI, 1.01-1.39), increased hospital stay (adjusted-risk ratio [RR], 1.10; 95% CI, 1.09-1.11) and increased post-ICU stay (adjusted-RR, 1.16; 95% CI, 1.14-1.17) when compared with workhours discharge. CONCLUSIONS: Afterhours discharge is common, occurring in 1 in 4 discharges, and is widely variable across ICUs. Patients discharged afterhours have greater risk of hospital mortality and prolonged hospitalization.

Association between afterhours admission to the intensive care unit, strained capacity, and mortality: a retrospective cohort study.

BACKGROUND: Admission to the intensive care unit (ICU) outside daytime hours has been shown to be variably associated with increased morbidity and mortality. We aimed to describe the characteristics and outcomes of patients admitted to the ICU afterhours (22:00-06:59 h) in a large Canadian health region. We further hypothesized that the association between afterhours admission and mortality would be modified by indicators of strained ICU capacity. METHODS: This is a population-based cohort study of 12,265 adults admitted to nine ICUs in Alberta from June 2012 to December 2014. We used a path-analysis modeling strategy and mixed-effects multivariate regression analysis to evaluate direct and integrated associations (mediated through Acute Physiology and Chronic Health Evaluation (APACHE) II score) between afterhours admission (22:00-06:59 h) and ICU mortality. Further analysis examined the effects of strained ICU capacity and varied definitions of afterhours and weekend admissions. ICU occupancy ≥ 90% or clustering of admissions (≥ 0.15, defined as number of admissions 2 h before or after the index admission, divided by the number of ICU beds) were used as indicators of strained capacity. RESULTS: Of 12,265 admissions, 34.7% (n = 4251) occurred afterhours. The proportion of afterhours admissions varied amongst ICUs (range 26.7-37.8%). Patients admitted afterhours were younger (median (IQR) 58 (44-70) vs 60 (47-70) years, p < 0.0001), more likely to have a medical diagnosis (75.9% vs 72.1%, p < 0.0001), and had higher APACHE II scores (20.9 (8.6) vs 19.9 (8.3), p < 0.0001). Crude ICU mortality was greater for those admitted afterhours (15.9% vs 14.1%, p = 0.007), but following multivariate adjustment there was no direct or integrated effect on ICU mortality (odds ratio (OR) 1.024; 95% confidence interval (CI) 0.923-1.135, p = 0.658). Furthermore, direct and integrated analysis showed no association of afterhours admission and hospital mortality (p = 0.90) or hospital length of stay (LOS) (p = 0.27), although ICU LOS was shorter (p = 0.049). Early-morning admission (00:00-06:59 h) with ICU occupancy ≥ 90% was associated with short-term (≤ 7 days) and all-cause ICU mortality. CONCLUSIONS: One-third of critically ill patients are admitted to the ICU afterhours. Afterhours ICU admission was not associated with greater mortality risk in most circumstances but was sensitive to strained ICU capacity.

Timing of onset of persistent critical illness: a multi-centre retrospective cohort study.

PURPOSE: Persistent critical illness has been described as a subtype of chronic critical illness, characterized as a transition after ICU admission where primary diagnosis and illness acuity are no better at predicting outcome than pre-hospital characteristics. Herein we describe the occurrence and outcomes associated with persistent critical illness in a large Canadian health region. METHODS: In this multi-center observational cohort study, all patients aged older than 14 years admitted to 12 ICUs in Alberta, Canada, between June 2012 and December 2014 were included. Primary outcome was in-hospital mortality. Predictors at ICU admission were separated into: (1) antecedent characteristics component (e.g., demographics, chronic health component of the APACHE II score, comorbid conditions); and (2) acute illness component (e.g., APACHE II score at admission, SOFA score, primary diagnostic category, surgical status, acute organ support). Using multiple statistical methods and randomly splitting the cohort into development and validation samples for risk scoring using logistic regression, we examined mortality prediction of each of these components to characterize the timing of transition to persistent critical illness. RESULTS: We included 17,783 patients with a median (IQR) age 61 years (49-71), 62% were male, and mean APACHE II score was 19.0 (7.9). In-hospital mortality was 16.8%. Among patients alive and in ICU, the acute illness component, which accurately predicted outcome at the time of admission [area under the receiver operating characteristics curve (AUC) 0.861; 95% CI 0.860-0.862], progressively lost predictive ability and was no longer more predictive than antecedent characteristics after 9 days. This transition defined the onset of persistent critical illness and comprised 16.1% (n = 2856) of the cohort. Transition ranged between 5 and 21 days across subgroups. In-hospital mortality was greater for those with persistent critical illness [23.9% vs. 15.5%, odds ratio (OR) 1.54; 95% CI 1.43-1.67, p < 0.001]. Persistently critically ill patients accounted for 54.5% of 97844 ICU bed-days and 36.3% of 420119 hospital bed-days, respectively. CONCLUSIONS: Persistent critical illness occurred in one in six patients admitted to Alberta ICUs and portended greater risk of death, prolonged ICU and hospital stay, and disproportionate use of health resources compared to patients without persistent critical illness.

Association between strained capacity and mortality among patients admitted to intensive care: A path-analysis modeling strategy.

PURPOSE: To evaluate the associations between strained ICU capacity and patient outcomes. METHODS: Multi-center population-based cohort study of nine integrated ICUs in Alberta, Canada. Path-analysis modeling was adopted to investigate direct and indirect associations between strain (available beds ≤1; occupancy ≥95%) and outcomes. Mixed-effects multivariate regression was used to measure the association between strain and acuity (APACHE II score), and both acuity and strain measures on ICU mortality and length of stay. RESULTS: 12,265 admissions comprise the study cohort. Available beds ≤1 and occupancy ≥95% occurred for 22.3% and 17.0% of admissions. Lower bed availability was associated with higher APACHE II score (p<0.0001). The direct effect of ≤1 available beds at ICU admission on ICU mortality was 11.6% (OR 1.116; 95% CI, 0.995-1.252). Integrating direct and indirect effects resulted in a 16.5% increased risk of ICU mortality (OR 1.165; 95% CI, 1.036-1.310), which exceeded the direct effect by 4.9%. Findings were similar with strain defined as occupancy ≥95%. Strain was associated with shorter ICU stay, primarily mediated by greater acuity. CONCLUSIONS: Strained capacity was associated with increased ICU mortality, partly mediated through greater illness acuity. Future work should consider both the direct and indirect relationships of strain on outcomes.