Table 1

Characteristics of studies included in quantitative analysis and risk of bias ratings

Study	Year	No	Age	Regimen 1	Regimen 2	Regimen 3	Regimen 4	Main outcomes reported in the study	Context	Randomisation	Allocation concealment	Blinding	Incomplete outcomes	Selective reporting	Other
Gremse et al 4	1996	34	3–17 years	Sodium phosphate	PEG	N/A	N/A	The bowel preparation was excellent or good in 18/19 patients in sodium phosphate Group and 6/15 in PEG group. The incidence of vomiting was similar in both groups, but abdominal pain occurred more in PEG group.	Elective colonoscopy	Unclear—one of the authors randomised patients into groups	One of the authors assigned the patients to their groups, also perform colonoscopies	Appear single blind	Unclear, no ITT	High—details of adverse events not given	None
Sinha et al 6	2007	126	Mean 3 years	Sodium chloride	PEG	Ringer lactate	N/A	Bowel preparation was good in 35/40 in Nacl group, 49/55 in PEG group and 29/31 of lactate group. All three were similar in safety	Elective surgery	Unclear	Unclear	Appear single blind	Low risk	Unclear risk	None
Kierkus et al 8	2013	240	10–18 years	BPEG	PEG	Sennosides	N/A	There were no significant differences found for the proportions of participants with excellent/good (PEG: 35/79, BPEG: 26/79, sennosides: 25/76) bowel preparation	Elective colonoscopy	List created by independent person using block	Yes	Single blind	Low risk	Low risk	None
Kumar and Hussain12	2013	30	1 month–7 years	Normal saline	PEG	N/A	N/A	Bowel preparation was rated as good/very good in 14/15 in the PEG group and 15/15 in the NS group. More symptomatic complications were noted in the NS group (7) than in PEG group (1).	Various surgical procedures	Unclear	Unclear	Unclear	Low risk	Low	None apparent
Turner et al 11	2009	83	4–18 years	Pico-Salax	PEG-ELS	N/A	N/A	Bowel preparation was judged as good/excellent in 33/43 of Pico-sSalax group and 32/40 PEG-ELS group. No significant difference in safety was found between the groups	Elective colonoscopy	Computer-generated list in blocks of 6	Yes	Single blind	Yes	Low risk	Funded by pharma but not involved in study
Di Nardo et al 10	2014	299	2 years–18 years	PEG-ELS with simethicone	PEG with citrate and bisacodyl	PEG 3350 with ascorbic acid	Sodium picosulfate, Magesium oxide+citric acid	No statistical difference was found between any group using the Boston scoring system (p=0.910). No serious adverse events occurred in any group.	Elective colonoscopy	Computer generated list	Opaque sealed signed envelop	Unblind	Low risk	Low risk	None apparent
Dahshan et al 9	1999	70	3–20 years	Magnesium citrate with X-prep	Dulcolax and Fleet Enema	Golytely (PEG)	N/A	Bowel preparation was rated as excellent in 6/20 of X-prep group, 2/19 Dulcolax and 15/31 of PEG group. Statistically more side effects were reported in the PEG group.	Elective colonoscopy	No detail given	Unclear	Single blind	Low risk	Low risk	None apparent
Terry et al 7	2013	33	6–21 years	PEG-P	Senna	N/A	N/A	Bowel preparation was rated as excellent/good in 14/16 of PEG-P group and 4/14 of the senna group. Both were well tolerated by patient-graded ease of preparation.	Elective colonoscopy	Randomly chosen preparation packet	A nurse administer – no further details	Single blind	Low risk	Low risk	None apparent
da Silva et al 13	1997	30	3–14 years	Sodium phosphate	PEG	N/A	N/A	Excellent-to-good colonic cleansing was achieved in 10/14 in sodium phosphate group and 11/15 of PEG group. Patients recorded less discomfort with orally administered Fleet than with high-volume balanced-lavage preparation	Elective colonoscopy	Computer generated and randomly assigned	Unclear risk	Unclear risk	Unclear	High risk	None apparent

BPEG, polyethylene glycol combined with bisacodyl; ITT, intention to treat; N/A, not applicable; NACL, sodium chloride; NS, normal saline; PEG, polyethylene glycol; PEG-ELS, polyethylene glycol-electrolyte lavage solution; PEG-P, polyethylene glycol without electrolytes.