Table 2.
Findings of included studies.
| Author (year) | Unadjusted mortality (univariate associations) | Adjusted mortality (multivariate associations) |
|---|---|---|
| Agustin et al. [23] (2017) | No significant difference in hospital mortality between pts with ED LOS ≥ 6 hrs and those with ED LOS < 6 hrs: 24.7% vs. 22.6%, OR 1.12, 95% CI 0.65-1.93, p = 0.685 | ED LOS ≥ 6 hrs was not associated with higher hospital mortality: OR 1.23, 95% CI 0.67-2.25, p = 0.510 |
| Al-Qahtani et al. [24] (2017) | Pts with ED LOS between 6 and 24 hrs and >24 hrs had higher hospital mortality than those with ED LOS < 6 hrs: 29.1% and 37.2% vs. 22.5%, respectively, p < 0.001 No significant difference in ICU mortality between pts with ED LOS between 6 and 24 hrs and >24 hrs and those with ED LOS < 6 hrs: 21.8% and 25.2% vs. 18.1%, p = 0.130 |
ED LOS > 24 hrs was independently associated with higher hospital mortality: OR 2.09, 95% CI 1.22-3.60, p = 0.007 ED LOS > 24 hrs was independently associated with higher ICU mortality: OR 1.90, 95% CI 1.02-3.54, p = 0.040 |
| Arulkumaran et al. [25] (2017) | Not reported | Remaining outside ICU for ≤4 hrs and >4 hrs were independently associated with higher hospital mortality: OR 1.08, 95% CI 1.01-1.17, and OR 1.17, 95% CI 1.04-1.32, p = 0.004, respectively |
| Bing-Hua [14] (2014) | No significant difference in ICU mortality between pts immediately admitted to ICU and those boarding in PACU: 8.6% vs. 6.7%, p = 0.311 Pts boarding in PACU for >6 hrs had higher hospital mortality than those immediately admitted to ICU: 15.4% vs. 6.7%, p < 0.001 |
Boarding in PACU for >6 hrs was independently associated with higher ICU mortality: OR 5.32, 95% CI 1.25-22.60, p = 0.024 |
| Cardoso et al. [13] (2011) | Pts not immediately admitted to the ICU had higher ICU mortality than immediately admitted ones: 50.0% vs. 37.6%, OR 1.66, 95% CI 1.08-2.56, p < 0.01 | Each hr of delayed ICU admission was independently associated with 1.0% increase in hospital mortality and 1.5% increase in ICU mortality: HR 1.01, 95% CI 1.00-1.02, p = 0.014, and HR 1.02, 95% CI 1.01-1.02, p = 0.001, respectively |
| Chalfin et al. [1] (2007) | Pts with ED LOS > 6 hrs had higher hospital and ICU mortality than those with ED LOS < 6 hrs: 17.4% vs. 12.9%, p < 0.001, and 10.7% vs. 8.4%, p = 0.009, respectively | ED LOS > 6 hrs was independently associated with higher hospital mortality: OR 1.41, 95% CI 1.12-1.78, p = 0.004 |
| Chiavone and Rasslan [26] (2005) | Pts with PACU LOS > 12 hrs had higher ICU mortality than those with PACU LOS ≤ 12 hrs: 54.9% vs. 26.1%, OR 3.45, 95% CI 1.22-9.78, p = 0.018 | Not reported |
| Choi et al. [27] (2021) | No significant difference in hospital mortality between pts with ED LOS > 6 hrs and those with ED LOS ≤ 6 hrs: 31.5% vs. 27.9%, OR 1.19, 95% CI 0.78-1.81, p = 0.418 Pts with ED LOS > 24 hrs had higher ICU mortality than those with ED LOS ≤ 24 hrs: 41.9% vs. 27.2%, OR 1.93, 95% CI 1.18-3.14, p = 0.008 |
ED LOS (as continuous variable) was independently associated with higher hospital mortality: OR 1.01, 95% CI 1.00-1.02, p = 0.039 |
| Churpek et al. [28] (2016) | Pts admitted to ICU after >6 hrs had higher hospital mortality than those admitted within 6 hrs: 33.2% vs. 24.5%, OR 1.53, 95% CI 1.33-1.77, p < 0.001 | Each hr of delayed ICU admission was independently associated with 3.0% increase in hospital mortality, p < 0.001 |
| Flabouris et al. [29] (2012) | Pts initially admitted to general wards had higher hospital mortality than those directly admitted to ICU: 34.9% vs. 23.3%, OR 1.76, 95% CI 1.46-2.13, p < 0.01 | Not reported |
| García-Gigorro et al. [9] (2017) | Pts with ED LOS > 5 hrs had higher hospital and ICU mortality than those with ED LOS ≤ 5 hrs: 21.7% vs. 8.6%, p = 0.003, and 17.8% vs. 7.1%, p = 0.006, respectively | ED LOS > 5 hrs was independently associated with higher hospital mortality: OR 3.13, 95% CI 1.86-5.22 |
| Gillies et al. [12] (2017) | Pts admitted to ICU after ≤7 days had higher hospital, perioperative (30-day), and ICU mortality than immediately admitted ones: 24.3% vs. 14.0%, p < 0.01, 20.9% vs. 12.1%, p < 0.01, and 15.2% vs. 6.9%, p < 0.01, respectively | Admission to ICU after ≤7 days was independently associated with higher perioperative (30-day) mortality: OR 2.39, 95% CI 2.01-2.84, p < 0.01 |
| Hsieh et al. [30] (2017) | Pts with ED LOS > 1 hr had higher hospital mortality than those with ED LOS ≤ 1 hr: 84.5% vs. 71.4%, OR 2.18, 95% CI 1.07-4.45, p = 0.03 | ED LOS > 1 hr was independently associated with higher hospital mortality: OR 2.19, 95% CI 1.04-4.64, p = 0.04 |
| Hung et al. [11] (2014) | No significant difference in 21-ventilator-day mortality between pts with ED LOS > 4 hrs and those with ED LOS ≤ 4 hrs: OR 1.17, 95% CI 0.98-1.39, p = 0.093 | ED LOS > 4 hrs was independently associated with higher 21-ventilator-day mortality: OR 1.41, 95% CI 1.05-1.89, p = 0.024 |
| Intas et al. [31] (2012) | Pts with ED LOS ≥ 6 hrs had higher hospital and ICU mortality than those with ED LOS < 6 hrs: 62.9% vs. 46.7%, p = 0.001, and 43.5% vs. 22.2%, p < 0.001, respectively | ED LOS ≥ 6 hrs was independently associated with higher hospital mortality: OR 5.73, 95% CI 2.25-13.71, p < 0.001 |
| Khan et al. [2] (2016) | No significant difference in hospital mortality between pts with ED LOS > 6 hrs and those with ED LOS ≤ 6 hrs: 27.3% vs. 20.7%, OR 1.44, 95% CI 0.86-2.40, p = 0.160 | Not reported |
| Leong et al. [17] (2019) | Pts admitted to ICU after ≤24 hrs had higher 30-day and 90-day mortality than directly admitted ones: 15.0% vs. 9.9%, p = 0.03, and 20% vs. 13%, p = 0.005, respectively | Admission to ICU after ≤24 hrs was not associated with higher 30-day mortality: OR 0.84, 95% CI 0.60-1.17, p = 0.296 |
| Liu et al. [32] (2012) | Pts admitted to ICU after ≤24 hrs had higher hospital mortality than directly admitted ones: 11.6% vs. 8.5%, OR 1.41, 95% CI 1.30-1.54, p < 0.01 | Not reported |
| Louriz et al. [33] (2012) | No significant difference in hospital mortality between pts admitted from wards and immediately admitted ones: 43.8% vs. 33.3%, HR 1.11, 95% CI 0.74-1.68, p = 0.59 | Delayed admission to ICU from wards was not associated with higher hospital mortality: OR 1.02, 95% CI 0.67-1.57, p = 0.89 |
| Molina et al. [6] (2014) | Pts admitted to ICU after ≤24 hrs had higher hospital and 60-day mortality than directly admitted ones: 32.2% vs. 27.0%, p < 0.01, and 52.3% vs. 43.3%, p < 0.01, respectively | Admission to ICU after ≤24 hrs was independently associated with higher hospital and 60-day mortality: OR 3.07, 95% CI 1.39-6.80, and OR 3.09, 95% CI 1.40-6.83, respectively |
| O'Callaghan et al. [34] (2012) | No significant difference in hospital and ICU mortality between pts admitted to ICU after >3 hrs and directly admitted ones: 36.2% vs. 32.8%, p = 0.44, and 26.8% vs. 24.2%, p = 0.47, respectively | Admission to ICU after >3 hrs was not associated with higher ICU mortality: OR 1.27, 95% CI 0.81-2.01, p = 0.29 |
| Parkhe et al. [35] (2002) | Pts admitted to ICU after ≤24 hrs had higher hospital and ICU mortality than directly admitted ones: 34.8% vs. 14.1%, OR 3.5, 95% CI 1.5-7.8, p = 0.044, and 34.8% vs. 9.1%, OR 2.5, 95% CI 1.2-5.2, p = 0.007, respectively | Not reported |
| Phua et al. [36] (2010) | Pts admitted to ICU after ≤72 hrs had higher hospital mortality than directly admitted ones: 51.0% vs. 20.4%, p = 0.001 | Admission to ICU after ≤72 hrs was independently associated with higher hospital mortality: OR 9.61, 95% CI 2.32-39.78, p = 0.002 |
| Renaud et al. [37] (2009) | No significant difference in 28-day mortality between pts admitted to ICU after 2-3 days and directly admitted ones: 19.6% vs. 13.6%, OR 1.54, 95% CI 0.91-2.61, p = 0.11 | Admission to ICU after 2-3 days was independently associated with higher 28-day mortality: OR 2.48, 95% CI 1.21-5.08, p = 0.01 |
| Santos et al. [38] (2020) | No significant difference in hospital and ICU mortality between pts with ED LOS < 637 min and those with ED LOS ≥ 637 min: 30.8% vs. 36.9%, OR 1.31, 95% CI 0.70-2.46, p = 0.639, and 24.6% vs. 29.8%, OR 1.30, 95% CI 0.66-2.54, p = 0.707, respectively ED LOS (as continuous variable) was not associated with hospital mortality: OR 1.20, 95% CI 0.68-2.13, p = 0.527 |
Not reported |
| Serviá et al. [39] (2012) | Pts with ED LOS > 120 min had higher hospital mortality than those with ED LOS ≤ 120 min: 28.7% vs. 11.6%, OR 3.14, 95% CI 1.59-6.21, p = 0.011 | ED LOS > 120 min was not associated with higher hospital mortality (OR not reported) |
| Simpson et al. [40] (2005) | Pts not directly admitted to ICU had higher hospital and ICU mortality than directly admitted ones: 46.4% vs. 32.7%, OR 1.78, 95% CI 1.64-1.94, p < 0.001, and 36.8% vs. 26.2%, OR 1.64, 95% CI 1.50-1.79, p < 0.001, respectively | Not reported |
| Stohl et al. [10] (2019) | No significant difference in 28-day mortality between pts admitted to ICU after ≥4 hrs and those admitted within 4 hrs: 25.2% vs. 29.6%, OR 0.80, 95% CI 0.63-1.01, p = 0.06 | Admission to ICU after ≥4 hrs was not associated with higher 28-day, hospital, ICU, and 3-month mortality: OR 1.10, 95% CI 0.85-1.43, p = 0.45, OR 1.01, 95% CI 0.77-1.32, p = 0.94, OR 0.95, 95% CI 0.71-1.26, p = 0.71, and OR 1.07, 95% CI 0.84-1.38, p = 0.58, respectively |
| Tilluckdharry et al. [41] (2005) | No significant difference in hospital mortality between pts with ED LOS ≥ 24 hrs and those with ED LOS < 24 hrs: 26.8% vs. 26.9%, OR 1.0, 95% CI 0.61-1.65, p = 0.5 | Not reported |
| Tsakiridou et al. [42] (2018) | No significant difference in hospital mortality between pts admitted to ICU after ≥24 hrs and those admitted within 24 hrs: 40.6% vs. 30.9%, OR 1.53, 95% CI 0.64-3.67, p = 0.337 | Not reported |
| Yergens et al. [43] (2015) | Pts with ED LOS > 7 hrs had higher hospital mortality than those with ED LOS ≤ 7 hrs: 74.6% vs. 66.4%, OR 1.48, 95% CI 1.18-1.86, p = 0.001 | Not reported |
| Young et al. [44] (2003) | Pts admitted after ≥4 hrs had higher hospital mortality than those admitted within 4 hrs: 41.1% vs. 11.4%, OR 5.40, 95% CI 1.68-17.39, p = 0.004 | Not reported |
| Zhang et al. [45] (2019) | Pts with ED LOS of 12-24 hrs and >24 hrs had higher hospital mortality than those with ED LOS < 6 hrs: 31.9% and 31.8% vs. 21.4%, p < 0.001, respectively | ED LOS of 12-24 hrs and >24 hrs was independently associated with higher hospital mortality: OR 1.82, 95% CI 1.28-2.58, p < 0.001, and OR 1.79, 95% CI 1.27-2.52, p < 0.001, respectively |
| Zhou et al. [46] (2015) | No significant difference in ICU mortality between pts immediately admitted to ICU and those boarding in PACU: 5.2% vs. 3.8%, ΟR 0.72, 95% CI 0.17-3.07, p = 0.681 | Not reported |
ICU: intensive care unit; ED: emergency department; PACU: postanesthesia care unit; LOS: length of stay; OR: odds ratio; HR: hazard ratio; CI: confidence interval; pts: patients; hr: hour; min: minutes.