Split-dose vs same-day bowel preparation for afternoon colonoscopies: A meta-analysis of randomized controlled trials

Table 1 Description of studies included in the meta-analysis

Ref.	Country	Number of patients (n)	Bowel preparation times (dose 1)	Patients per group (n)	Bowel preparation scale	Satisfactory bowel preparations (n)	OBPS (mean score ± SD)
Parra-Blanco et al[16], 2006	Spain	88	Same day PEG 3 L	43	Ottawa	34	ND
			Split-dose NaP 45 mL/45 mL	45	Ottawa	36	ND
Kang et al[24], 2014	South Korea	196	Same day NaP 1/1	97	Ottawa	59	4.05 ± 1.56
			Split-dose PEG 2 L/2 L	99	Ottawa	71	3.8 ± 1.55
Shah et al[17], 2014	India	159	Same day PEG 2 L	80	Ottawa	ND	6.02 ± 1.34
			Split-dose PEG 1 L/1 L	79	Ottawa	ND	5.52 ± 1.23
Cesaro et al[18], 2013	Italy	101	Same day Halflytely 2 L/10-20 mg Bisacodyl	50	Ottawa	ND	2.78 ± 1.95
			Split-dose PEG 3 L/1 L	51	Ottawa	ND	3.41 ± 1.90
de Leone et al[19], 2013	Italy	154	Same day Halflytely 2 L/10-20 mg Bisacodyl	78	Ottawa	70	3.09 ± 2.4
			Split-dose PEG 2 L/2 L	76	Ottawa	70	2.39 ± 2.55
Kim et al[25], 2014	South Korea	100	Same day PEG 4 L	50	Ottawa	41	4.98 ± 1.78
			Split-dose PEG 2 L/2 L	50	Ottawa	42	4.98 ± 1.57
Kotwal et al[20], 2014	United States	103	Same day PEG 3 L	51	Ottawa	ND	7.15 ± 3.58
			Split-dose PEG 2 L/2 L	52	Ottawa	ND	7.38 ± 3.65
Seo et al[21], 2013	South Korea	197	Same day PEG 2 L	97	Ottawa	72	3.76 ± 2.07
			Split-dose PEG 2 L/2 L	100	Ottawa	75	3.67 ± 1.57
Zhang et al[23], 2014	China	318	Same day PEG 2 L	159	Ottawa	126	4.4 ± 2.7
			Split-dose PEG 1 L/2 L	159	Ottawa	143	2.9 ± 2.4
Alkhairi et al[26], 2017	United States	300	Same day PEG 4 L	142	Ottawa	142	ND
			Split-dose PEG 2 L/2 L	158	Ottawa	156	ND
Castro et al[22], 2019	United States	130	Same day PEG 4 L	65	Ottawa	34	ND
			Split-dose PEG 2 L/2 L	65	Ottawa	31	ND

OBPS: Ottawa bowel preparation score; PEG: Polyethylene glycol; ND: Not detected.

Table 2 Quality assessment of studies included in meta-analysis based upon Cochrane’s Collaboration Risk of Bias tool

Ref.	Study design	Random sequence generation	Allocation concealment	Blinding	Blinding outcome assessment	Incomplete outcome data	Selective reporting	Other bias	Quality assessment
Parra-Blanco et al[16], 2006	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Kang et al[24], 2014	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Shah et al[17], 2014	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Cesaro et al[18], 2013	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
de Leone et al[19], 2013	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Kim et al[25], 2014	RCT	Not described	Adequate	Single-blinded	Adequate	None	None	None	Moderate
Kotwal et al[20], 2014	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Seo et al[21], 2013	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Zhang et al[23], 2014	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Castro et al[22], 2019	RCT	Adequate	Adequate	Single-blinded	Adequate	None	None	None	High
Alkhairi et al[26], 2017	RCT	Not described	Not described	Single-blinded	Adequate	None	None	None	Moderate

RCT: Randomized controlled trial.