Table 1.
Characteristics and assessment of risk for bias of included studies.
| Author (year) | Study design/country | Study population | Non-DA/DA group/incidence of DA | Significant differences in patient characteristics between non-DA and DA groups | NOS∗/RFB∗∗ |
|---|---|---|---|---|---|
| Agustin et al. [23] (2017) | Retrospective, single-center/US | 287 ED pts with severe sepsis and septic shock | Pts with ED LOS < 6 hrs (150)/pts with ED LOS ≥ 6 hrs (137)/47.7% | DA pts had lower initial lactate level | 9/4 |
| Al-Qahtani et al. [24] (2017) | Retrospective, single-center/Saudi Arabia | 940 ED pts | Pts with ED LOS < 6 hrs (227)/pts with ED LOS between 6 and 24 hrs (358) and >24 hrs (355)/75.9% | DA pts were older and had longer duration of mechanical ventilation | 9/3 |
| Arulkumaran et al. [25] (2017) | Prospective, multicenter/UK | 195,428 medical/surgical ward, obstetric/intermediate care areas, ED, and OR pts | Pts immediately admitted (187,133)/pts remaining outside ICU for ≤4 hrs (6,198) and >4 hrs (2,097)/4.2% | Not reported | 8/1 |
| Bing-Hua [14] (2014) | Retrospective, single-center/China | 2,279 postoperative pts | Pts immediately admitted (2,094)/pts boarding in PACU for ≤2, 2-4, 4-6, and >6 hrs (185)/8.1% | DA pts were older and more likely to have diabetes and chronic lung disease | 7/3 |
| Cardoso et al. [13] (2011) | Prospective, single-center/Brazil | 401 ED and general ward pts | Pts immediately admitted (125)/pts admitted from wards after ≤72 hrs (276)/68.8% | DA pts had more comorbidities | 9/2 |
| Chalfin et al. [1] (2007) | Retrospective, multicenter/US | 50,322 ED pts | Pts with ED LOS < 6 hrs (49,286)/pts with ED LOS ≥ 6 hrs (1,036)/2.1% | No differences were noted | 8/3 |
| Chiavone and Rasslan [26] (2005) | Prospective, single-center/Brazil | 94 postoperative pts after emergency surgery | Pts boarding in surgical unit for ≤12 hrs after the end of surgery (23)/pts boarding in surgical unit for >12 hrs (71)/75.5% | No differences were noted | 6/4 |
| Choi et al. [27] (2021) | Retrospective, multicenter/Republic of Korea | 439 ED pts > 65 years with infectious diseases | Pts with ED LOS ≤ 6 hrs (179)/pts with ED LOS > 6 hrs (260) and >24 hrs (86)/59.2% and 19.6%, respectively | Not reported | 8/4 |
| Churpek et al. [28] (2016) | Retrospective, multicenter/US | 3,789 medical/surgical ward pts | Pts admitted within 6 hrs (2,055)/pts admitted after ≥6 hrs (1,734)/45.7% | DA pts were older | 8/2 |
| Flabouris et al. [29] (2012) | Retrospective, single-center/Australia | 21,960 ED and general ward pts | Pts directly admitted from ED (21,481)/pts admitted from general wards (479)/2.2% | DA pts had higher clinical severity | 8/3 |
| García-Gigorro et al. [9] (2017) | Prospective and retrospective, single-center/Spain | 269 ED pts | Pts with ED LOS ≤ 5 hrs (140)/pts with ED LOS > 5 hrs (129)/48.0% | Not reported | 6/4 |
| Gillies et al. [12] (2017) | Retrospective, multicenter/UK | 13,591 postoperative pts (excluding cardiac surgery and neurosurgery) | Pts immediately admitted after surgery (1,116)/pts admitted from non-ICU settings after ≤7 days (12,475)/89.5% | DA pts were older and had higher operative severity and emergency surgical status | 9/1 |
| Hsieh et al. [30] (2017) | Retrospective, single-center/Taiwan | 267 ED pts with acute respiratory failure | Pts with ED LOS ≤ 1 hr (196)/pts with ED LOS > 1 hr (71)/26.6% | Not reported | 7/5 |
| Hung et al. [11] (2014) | Retrospective, single-center/Taiwan | 1,242 nontrauma ED pts with ventilatory support | Pts with ED LOS ≤ 4 hrs (337)/pts with ED LOS > 4 hrs (905)/72.9% | Not reported | 7/4 |
| Intas et al. [31] (2012) | Prospective, single-center/Greece | 200 intubated ED pts | Pts with ED LOS < 6 hrs (60)/pts with ED LOS ≥ 6 hrs (140)/70.0% | More DA pts were female and medical, had higher age, were more likely to manifest fever, and received more medicines | 8/3 |
| Khan et al. [2] (2016) | Retrospective, single-center/Pakistan | 325 ED pts | Pts with ED LOS ≤ 6 hrs (164)/pts with ED LOS > 6 hrs (161)/49.5% | DA pts had lower GCS scores, were less likely to have history of endocrine disease, and more likely to have history of CNS disease | 8/4 |
| Leong et al. [17] (2019) | Retrospective, single-center/US | 4,282 ED, OR, and ward pts | Pts directly admitted from ED or OR (3,862)/pts admitted from wards after ≤24 hrs (420)/9.8% | No differences were noted | 8/3 |
| Liu et al. [32] (2012) | Retrospective, multicenter/US | 36,298 ED and ward pts | Pts directly admitted from ED (29,929)/pts admitted from wards after ≤24 hrs (6,369)/17.5% | Not reported | 7/3 |
| Louriz et al. [33] (2012) | Retrospective, single-center/Morocco | 256 ED pts | Pts immediately admitted from ED (110)/pts admitted from wards (146)/57.0% | DA pts were older and had more comorbidities | 8/4 |
| Molina et al. [6] (2014) | Retrospective, single-center/Singapore | 698 ED and ward pts | Pts directly admitted from ED (490)/pts admitted from wards after ≤24 hrs (208)/29.8% | DA pts were older and less likely to undergo resuscitation or intubation in ED | 9/3 |
| O'Callaghan et al. [34] (2012) | Retrospective, single-center/UK | 1,609 ED, OR, and ward pts | Pts immediately admitted from ED (1,460)/pts admitted from ED, OR, or wards after >3 hrs (149)/9.3% | DA pts were more likely to have respiratory failure | 8/3 |
| Parkhe et al. [35] (2002) | Retrospective, single-center/Australia | 122 ED and ward pts | Pts directly admitted from ED (99)/pts admitted from wards after ≤24 hrs (23)/18.9% | DA pts were older, had higher clinical severity, and were more likely to have history of cardiac, respiratory, and gastrointestinal disease | 7/4 |
| Phua et al. [36] (2010) | Retrospective, single-center/Singapore | 103 ED and general ward pts | Pts directly admitted from ED (54)/pts admitted from general wards after ≤72 hrs (49)/47.6% | DA pts were older and less likely to have unstable vital signs and had better mental status | 8/3 |
| Renaud et al. [37] (2009) | Prospective, multicenter/US, France | 453 ED and medical ward pts | Pts directly admitted from ED (315)/pts admitted from medical wards after 2-3 days (138)/30.5% | DA pts were more likely to have cardiovascular disease or diabetes and less likely to have abnormal mental status, tachycardia, tachypnea, acidosis, and multilobar infiltrates | 9/1 |
| Santos et al. [38] (2020) | Prospective, single-center/Brazil | 206 ED pts | Pts with ED LOS < 637 min (65)/pts with ED LOS ≥ 637 min (141)/67.5% | DA pts were older and more likely to need assistance | 7/4 |
| Serviá et al. [39] (2012) | Prospective, single-center/Spain | 243 ED pts with severe trauma | Pts with ED LOS ≤ 120 min (122)/pts with ED LOS > 120 min (121)/49.8% | DA pts were older and less likely to manifest shock, be mechanically ventilated, and need blood transfusion and had higher injury severity | 8/3 |
| Simpson et al. [40] (2005) | Retrospective, multicenter/UK | 12,268 ED, ward, and intermediate care areas pts | Pts directly admitted from ED (9,389)/pts admitted from wards or intermediate care areas (2,879)/23.5% | DA pts were older and more likely to have severe past medical history | 8/3 |
| Stohl et al. [10] (2019) | Prospective, multinational | 3,175 pts of any hospital setting | Pts admitted within 4 hrs (2,754)/pts admitted after ≥4 hrs (421)/13.3% | Not reported | 8/2 |
| Tilluckdharry et al. [41] (2005) | Prospective, single-center/US | 443 ED pts | Pts with ED LOS < 24 hrs (339)/pts with ED LOS ≥ 24 hrs (104)/23.5% | No differences were noted | 8/5 |
| Tsakiridou et al. [42] (2018) | Prospective, single-center/Greece | 100 pts of any hospital setting with VAP | Pts admitted within 24 hrs (68)/pts admitted after ≥24 hrs (32)/32.0% | DA pts were more likely to be previously hospitalized and have chronic renal failure and received more antibiotics | 7/4 |
| Yergens et al. [43] (2015) | Retrospective, multicenter/Canada | 1,770 ED pts with sepsis or severe sepsis | Pts with ED LOS ≤ 7 hrs (488)/pts with ED LOS > 7 hrs (1,282)/72.4% | DA pts were older and had higher triage level | 8/3 |
| Young et al. [44] (2003) | Prospective, single-center/US | 91 ward pts with noncardiac diagnoses | Pts admitted within 4 hrs (35)/pts admitted after ≥4 hrs (56)/61.5% | No differences were noted | 8/3 |
| Zhang et al. [45] (2019) | Retrospective, single-center/China | 1,997 ED pts with sepsis | Pts with ED LOS < 6 hrs (1,306)/pts with ED LOS ≥ 6 hrs (691)/34.6% | Not reported | 8/4 |
| Zhou et al. [46] (2015) | Retrospective, single-center/China | 989 postoperative neurosurgical pts | Pts immediately admitted from OR (937)/pts boarding in PACU for ≤2 and >2 hrs (52)/5.3% | DA pts were less likely to be neurooncological | 6/4 |
ICU: intensive care unit; ED: emergency department, PACU: postanesthesia care unit; OR: operating room; LOS: length of stay; GCS: Glasgow Coma Scale; CNS: central nervous system; VAP: ventilator-associated pneumonia; DA: delayed ICU admission; NOS: Newcastle-Ottawa Scale; RFB: risk for bias according to additional criteria; pts: patients; hr: hour; min: minutes. ∗Score ranging from 0 to 9; the higher the score, the lower the risk for bias. ∗∗Score ranging from 0 to 7; the higher the score, the higher the risk for bias.