Table 1

Study characteristics

First author, publication year, country	Hospitals	Paediatric inpatients admissions, n	Inclusion period, year (months)	Type of hospital(s)	Academic level of hospital(s)	Inclusion and exclusion criteria of patients	Type of included units	Patient days, n	Age, (years) mean	LOS, (days) mean
General care population, GTT/TT methodology
Chapman 201440 GBR	Multicentre	3992	2008–2011 (46)	Mixed	Mixed	LOS >24 hours	Mixed—not explicitly stated	NS	NS	NS
Davenport 201741 ARG	Single centre	200	2013 (12)	Paediatric	NS	LOS ≥48 hours, if >1 hospitalisation the most recent one was included, no psychiatric patients and not for social reasons	ICU, neonatology, general care (multipurpose unit)	1690	4.4	8.5
Fajreldines 201945 ARG	Single centre	318	2015–2016 (13)	Tertiary care	Academic	LOS ≥48 hours, patient s<18 years	Neonatal care, PICU, nursery, paediatric	2257	3.0	NS
Kirkendall 201250 USA	Single centre	240	2009 (12)	Paediatric	Academic	LOS ≥24 hours, any age, no psychiatric and rehabilitation patients	Mixed—not explicitly stated	1206	7.8	5.1
Matlow 201254–56 CAN	Multicentre*	3552	2008–2009 (12)	Mixed*	Mixed*	LOS ≥24 hours, patients <19 years, no obstetrics, or psychiatric patients and external transfers (except newborns)	Surgical, internal medicine, emergency, maternal/obstetrics, other	14738†	4.1†*	4.5†*
Paredes Esteban 2015,58 ESP	Single centre	95	2014 (12)	NS	NS	Patients admitted to paediatric surgery, no patients with adverse events as the reason for admission	Surgical	406	6.7	4.2
Salimath 202046 60 IND	Single centre	520	NS (26‡)	Acute care	Academic	LOS≥24 hours, patients≤18 years, no psychiatric and rehabilitation patients	NICU, PICU, medicine, surgical, emergency and trauma†	2743†	NS	NS
Shah 200951 61 USA	Single centre	50	NS	Paediatric	Academic	Patients admitted to the otolaryngology service	Otolaryngology	87	NS	NS
Solevag, 201463 NOR	Single centre	494‡	2011 (3)	Acute care	Academic	Patients <18 years	Orthopaedic, surgical, ear/nose/ throat, medicine	2001†	6.8†	4.1†
Stockwell 201566 USA	Multicentre	600	2012 (1)	Paediatric	Academic	LOS between 24 hours and 6 months, patients <22 years, no rehabilitation, normal newborn nursery, day treatment, psychiatric or obstetric patients	NS	4372	6.2	7.3
Stockwell 201813 67 USA	Multicentre	3790	2007–2012 (72)	Mixed	Mixed	LOS ≥24 hours, patients age <18 years, no psychiatric (without a concurrent acute medical issue) or rehabilitation patients	Mixed—not explicitly stated	21 789	NS	3.0§
Stroupe 201868 USA	Single centre	100	2014 (12)	Paediatric	Academic	Admitted patients ≤18 years	General paediatric, surgery, PICU, other	411	6.7	3.8
Unbeck 201414 SWE	Single centre	600	2010 (12)	Acute care	Academic	LOS ≥24 hours, patient <19 years	Neonatal, surgical/orthopaedic, medicine, emergency medicine	5559	4.3	9.3
General care population, HMPS methodology
Brennan 199111 43 47 48 52 USA	Multicentre¶	6661**	1984 (12)	Acute care	Mixed¶	Admitted patients, no psychiatric patients	All types¶	NS	NS	NS
Davis 200242–44 NZL	Multicentre¶	1349†**	1998 (12)	Acute care	Mixed¶	Admitted patients, no day, psychiatric and rehabilitation-only patients	Mixed—not explicitly stated¶	4134‡	3.1†	3.1†
Letaief 201053 TUN	Single centre	116‡**	2005 (12)	Public	Academic	Admitted patients	Mixed—not explicitly stated	NS	NS	NS
Requena 201159 ESP	Multicentre	665	NS (NS)	NS	Mixed	LOS >24 hours, had a clinical history in the selected hospitals	NS	3318	NS	NS
Sommella 201464 ITA	Single centre	11‡**	2008 (12)	Acute care	NS	LOS >24 hours, no day hospital discharges	Medical, surgical, ICU¶	NS	NS	NS
Soop 200965 SWE	Multicentre ¶	159**	2003–2004 (12)	Acute care	Mixed¶	Admitted patients, no psychiatric, palliative care, rehabilitation, and day-only patients	Mixed—not explicitly stated¶	NS	NS	NS
Wilson 199512 AUS	Multicentre¶	2020**	1992 (12)	Acute care	Mixed¶	Admitted patients, no psychiatric and day-only patients	Different kind of medical and surgical†	8697†	4.1†	4.3†
Woods 200569 70 74 USA	Multicentre¶	3719**	1992 (12)	Profit/non-profit, government	Mixed¶	Admitted patients, no psychiatric, rehabilitation and drug/alcohol treatment patients	Mixed—not explicitly stated	NS	NS	NS
Zegers, 200933 75 NLD	Multicentre¶	330**	2004 (12)	Acute care	Mixed¶	LOS of >24 hours, no psychiatric, obstetrics and <1 year patients	Mixed—explicitly stated¶	NS	NS	NS
Intensive care population, GTT/TT methodology††
Agarwal 201038 USA	Multicentre	734	2005 (4)	Mixed	Mixed	LOS ≥48 hours, no postoperative cardiac patients	PICU	5201	6.3	7.1
Barrionuevo 201039 ARG	Single centre	484	2006 (12)	Public	NS	LOS >24 hours	NICU	6465†	NS	13.4†
Hooper 201448 AUS	Single centre	59	2011 (3)	Paediatric	Academic	Admitted patients	PICU	164	NS	2.8
Jorro-Baron 202149 ARG	Multicentre	1465	2018–2019 (11)	Public	NS	LOS ≥24 hours, patients <18 years and admitted for acute care	PICU	15 842	4.6†	10.8†
Larsen 20078 USA	Single centre	259	2002–2003 (12)	Paediatric	Academic	Admitted patients	PICU	962†	NS	1.6§
Matlow 201254–56 CAN	Multicentre*	117	2008–2009 (12)	Mixed*	Mixed*	LOS ≥24 hours, patients <19 years, no obstetrics or psychiatric patients and external transfers (except newborns)	NICU, PICU	1574†	0.0†	13.5†
Maziero 202057 BRA	Multicentre	79	2017–2018 (NS)	Public	NS	Admitted patients	NICU, PICU	NS	NS	NS
Sharek 200662 USA/CAN	Multicentre	749	2004–2005 (3)	Mixed	Mixed	LOS ≥48 hours	NICU	17 106	NS	22.8
Ventura 201271 BRA	Single centre	218	2009 (6)	NS	NS	LOS ≥48 hours	NICU	2958	NS	13.5
Verlaat, 201872 NLD	Multicentre	48	2006–2012 (72)	NS	NS	LOS ≥2 hours, patient <18 years, no patients with corrected age <36 weeks (GA)	PICU	608†	6.4	12.7†
Vermeulen 201473 ZAF	Single centre	80‡‡	2012 (4)	Paediatric	Academic	LOS >48 hours, patients included only once if >1 admission	PICU	512	NS	4.0§

*Outcome for the total cohort.
†Additional data from authors.
‡Calculations are made.
§Median.
¶Information for the total cohort in a study with both paediatric and adult patients, information for the paediatric cohort not reported.
**Paediatric cohort.
††Studies using the HMPS methodology did not predominantly include intensive care patients.
‡‡Retrospective cohort.
Academic, academic medical centre/university hospital; Adm, admission; GA, gestational age; GTT, Global Trigger Tool; HMPS, Harvard Medical Practice Study; ICU, Intensive care unit; LOS, length of stay; Mixed, both paediatric and adult hospital type; NICU, neonatal intensive care unit; NS, not specified; PICU, paediatric intensive care unit; TT, Trigger Tool.