Higher dose of simethicone decreases colonic bubbles and increases prep tolerance and quality of bowel prep: Meta-analysis of randomized controlled trials

Table 1 Characteristics of studies included in the meta-analysis

Ref.	Country	No. of patientsSimethicone/placebo	Bowel preparation used	Simethicone	Timing of Simethicone	Timing of bowel preparation	Diet prior to colonoscopy
McNally et al[19]	United States	49/48	6L PEG	160 mg	Mixed with PEG	Not clear	NA
Shaver et al[18]	United States	102/102	5L PEG	75 mL (30% simethicone)	45 mL before and 30 mL after ingestion of PEG	Night before	NA
Lazzaroni et al[13]	Italy	57/48	4L PEG	120 mg	Mixed with PEG	Split dose	NA
Sudduth et al[17]	United States	42/44	45 mL NaP × 2 doses	320 mg	160 mg after each dose of 45 mL NaP	Split dose	Clear liquid the day before
Altintas et al[14]	Turkey	82/83	90 mL NaP/133 mL NaP	300 mg	Capsule containing simethicone given 3 times/d × 5 d	Split dose	Watery or low fiber diet × 5 d
Tongprasert et al[12]	Thailand	62/60	45 mL NaP × 2 doses	480 mg	240 mg with each 45 mL NaP	NA	Low residue the day before
Jansen et al[16]	United States	177/193	4L PEG/PEG-Asc	200 mg (20 mL 10 mg/mL)	20 mL with the last L of PEG	Split dose	NA
Matro et al[15]	United States	62/61	PEG-Asc	400 mg	Added to PEG	Split dose	Low residue for breakfast (the day before), followed by clear liquid
Yoo et al[11]	South Korea	130/130	PEG-Asc	400 mg	Added to the last 500 mL of clear fluid	Split dose	Low residue × 3 days/clear liquid the night before
Zhang et al[9]	China	289/290	2L PEG	1200 mg	Added to PEG	Day of procedure	Low residue the day before
Bai et al[10]	China	294/289	2L PEG	1200 mg (30 mL, 40 mg/mL)	Added to PEG	Day of procedure	Low residue/clear liquid the night before

PEG: Polyethylene glycol; NaP: Sodium phosphate; N/A: Not available.

Table 2 Sensitivity analyses

	PEG purgatives	NaP purgatives	Simethicone dose above the mean (478 mg)	Simethicone dose below the mean(478 mg)
Inadequate bowel preparation	0.44 (0.26-0.73), P = 0.002, n = 6	0.82 (0.41-1.67), P = 0.59, n = 2	0.61 (0.38-0.98), P = 0.04, n = 4	0.29 (0.07-1.18), P = 0.08, n = 4
Significant bubbles	1.42 (1.2-1.7), P < 0.0001, n = 7	1.84 (1.1-2.9), P = 0.01, n = 2	1.79 (1.26-2.53), P = 0.001, n = 3	1.37 (1.17-1.59), P < 0.0001, n = 6
ADR	NA	NA	1.08 (1.03-1.15), P = 0.003, n = 2	1.0 (0.85-1.19), P = 0.98, n = 2

PEG: Polyethylene glycol; NaP: Sodium phosphate; N/A: Not available; n: Number of studies; ADR: Adenoma detection rate.