Impact of simethicone on bowel cleansing during colonoscopy in Chinese patients

Table 1 Baseline characteristics between the 4 L polyethylene glycol and 3 L polyethylene glycol plus simethicone groups

Variable	4-P (n = 145)	3-PS (n = 146)	P value1
Age, yr, (mean ± SD)	48.3 ± 12.1	47.9 ± 13.5	0.79
Male, n (%)	74 (51.0)	70 (47.9)	0.60
Diabetes, n (%)	12 (8.3)	9 (6.2)	0.49
Indication for colonoscopy, n (%)
Rectal bleeding	23 (15.9)	27 (18.5)	0.55
Diarrhea	22 (15.2)	28 (19.2)	0.37
Constipation	18 (12.4)	14 (9.6)	0.44
Abdominal discomfort	46 (31.7)	34 (23.3)	0.11
Surveillance/screening	20 (13.8)	30 (20.5)	0.13
Polypectomy/resection	12 (8.3)	10 (6.8)	0.65
Other	4 (2.7)	3 (2.1)	0.70

¹Statistical significance between groups was tested by Student t test or χ² analysis. 4-P: 4 L polyethylene glycol; 3-PS: 3 L polyethylene glycol plus simethicone.

Table 2 Outcomes of bowel preparation between the 4 L polyethylene glycol and 3 L polyethylene glycol plus simethicone groups

Variable	4-P (n = 145)	3-PS (n = 146)	P value1
Cecal intubation success, %	100	100	1
Cecal intubation time (mean ± SD), min	7.6 ± 1.9	7.8 ± 1.9	0.37
Withdrawal time (mean ± SD), min	9.6 ± 2.3	8.8 ± 3.4	0.02
Adenoma, n (%)	22 (15.2)	24 (16.4)	0.77
Polyp, n (%)	46 (31.7)	51 (35.0)	0.56
Colitis, n (%)	13 (9.0)	16 (11.0)	0.57
Normal, n (%)	61 (42.1)	57 (39.0)	0.60
Others, n (%)	7 (4.8)	5 (3.4)	0.55
BBPS
Total score (mean ± SD)	7.11 ± 1.52	7.06 ± 1.73	0.79
Right colon (mean ± SD)	2.21 ± 0.78	2.37 ± 0.54	0.04
Transverse colon (mean ± SD)	2.56 ± 0.50	2.44 ± 0.77	0.12
Left colon (mean ± SD)	2.34 ± 0.72	2.25 ± 0.84	0.33
BBPS ≥ 6, n (%)	136 (93.8)	132 (90.4)	0.29
Bubble score, mean (SD)	2.85 ± 1.91	1.21 ± 1.57	< 0.001
Left colon2	0.68 ± 0.80	0.27 ± 0.50	< 0.001
Transverse colon	0.64 ± 0.75	0.25 ± 0.51	< 0.001
Right colon3	1.52 ± 1.06	0.66 ± 0.96	< 0.001
Total number of adenomas	35	56	0.009
Adenoma location, n (%)
Proximal4	16 (45.7)	30 (53.6)	0.03
Distal5	19 (54.3)	26 (46.4)	0.27
Adenoma size, n (%)
≤ 5 mm	19 (54.3)	32 (57.1)	0.05
> 5 mm	16 (45.7)	24 (42.9)	0.18
Willingness to repeat bowel preparation, n (%)	111 (76.6)	128 (87.7)	0.01

¹Statistical significance between groups was tested by Student t test or χ² analysis.

²Left colon, including the descending colon, sigmoid colon, and rectum.

³Right colon, including the cecum and ascending colon.

⁴Proximal colon, including the cecum, ascending colon, and hepatic flexure colon.

⁵Distal colon, including the splenic flexure, descending colon, sigmoid colon, and rectum.

4-P: 4 L polyethylene glycol; 3-PS: 3 L polyethylene glycol plus simethicone; BBPS: Boston bowel preparation scale.

Table 3 Adverse events between the 4 L polyethylene glycol and 3 L polyethylene glycol plus simethicone groups

Symptom	4L (n = 145)	3L + S (n = 146)	P value1
Adverse events, n (%)	67 (46.2)	58 (39.7)	0.26
Nausea, n (%)	53 (36.6)	32 (22.0)	0.006
Abdominal pain, n (%)	13 (9.0)	12 (8.2)	0.82
Vomiting, n (%)	18 (12.4)	12 (8.2)	0.24
Bloating, n (%)	58 (40)	30 (20.5)	0.0004
Sleep disturbance, n (%)	60 (41.4)	50 (34.2)	0.21

¹Statistical significance between groups was tested by Student t test or χ² analysis.