Prospective randomized controlled trial evaluating cap-assisted colonoscopy vs standard colonoscopy

Table 1 Baseline characteristics of all patients n (%)

	CAC (n = 200)	SC (n = 200)	P value
Sex (male)	102 (51.0)	88 (44.0)	0.16
Age (yr) (mean ± SD)	53.8 ± 15.1	53.6 ± 14.8	0.89
Previous difficult colonoscopy	19 (9.5)	15 (7.5)	0.65
Known diverticular disease	8 (0.04)	11 (0.06)	0.74
Previous pelvic surgery	25 (12.5)	26 (13.0)	0.80
Gastroscopy at the same time	74 (37.0)	89 (44.5)	0.17
Indications
CRC screening	38 (19.0)	35 (17.5)
Rectal bleeding	37 (18.5)	32 (16.0)
Abdominal pain	32 (16.0)	33 (16.5)
Polyp follow up	30 (15.0)	27 (13.5)
Change in bowel habit	18 (9.0)	28 (14.0)
Others	45 (22.5)	45 (22.5)	0.58
Endoscopist
Specialist	41 (20.5)	49 (24.5)
Trainee	159 (79.5)	151 (75.5)	0.34
Bowel preparation
Good	107 (54.0)	130 (65.7)
Satisfactory	71 (35.9)	53 (26.8)
Poor	20 (10.1)	15 (7.6)	0.10
Scopes used
P160/P180	137 (66.5)	143 (70.5)
A160/A180	63 (32.0)	57 (28.5)	0.61

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; CRC: Colorectal cancer.

Table 2 Primary outcomes: performance of colonoscopy n (%)

	CAC	SC	P value
Cecal intubation rate	192/200 (96.0)	195/200 (97.0)	0.401
Cecal intubation rate by trainees	140/159 (88.1)	128/151 (84.8)	0.401
Ileal intubation rate	165/200 (82.5)	158/200 (79.0)	0.381
Ileal intubation rate by trainees	126/159 (79.2)	115/151 (76.2)	0.511
Cecal time (min) (mean ± SD) (n = 387)	9.94 ± 7.05	10.34 ± 6.82	0.212
Trainee cecal time (min) (mean ± SD) (n = 268)	10.72 ± 6.75	9.66 ± 4.86	0.642
Total colonoscopy time (min) (mean ± SD) (n = 387)	23.24 ± 13.95	22.56 ± 9.94	0.862
Trainee total colonoscopy time (min) (mean ± SD) (n = 268)	25.97 ± 1.22	23.70 ± 0.72	0.472

¹χ² test;

²Mann-Whitney test. CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy.

Table 3 Multivariate analysis of determinants of faster cecal intubation time

Independent predictors	B1	95% CI	P value
Consultant	0.55	0.47-0.63	< 0.001
Female sex	1.38	1.22-1.57	< 0.001
Use of hyoscine	1.48	1.21-1.81	< 0.001
Poor preparation	1.33	1.07-1.66	0.01

¹Average increase in cecal time per unit increase in the explanatory variable. e.g. the cecal time of consultants was 0.55 (95% CI: 0.47-0.63) times that of trainees.

Table 4 Secondary outcomes: polyp detection rate n (%)

	CAC	SC	P value
Subjects with polyps (n = 387)	63/192 (32.8)	61/195 (31.3)	0.751
Subjects aged ≥ 50 yr with polyps (n = 246)	51/118 (43.2)	46/128 (35.9)	0.241
Total number of polyps	147	107	0.592
Total number of polyps with size ≤ 5 mm	121	84	0.452
Total number of adenomas	75	55	0.262
Total number of advanced adenomas	23	14	0.522

¹χ² test;

²Mann-Whitney test. CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy.

Table 5 Multivariate analysis of determinants of higher polyp detection rate

Independent predictors	OR	95% CI	P value
Age	1.450	1.213-1.734	< 0.001
Previous abdominal surgery	0.559	0.322-0.971	0.039
Having EGD on the same setting	0.451	0.266-0.765	0.003
Consultant	0.460	0.250-0.845	0.012
Use of hyoscine	2.877	1.374-6.026	0.005
Indication: polyp follow-up	2.722	1.342-5.523	0.006

EGD: Esophago-gastro-duodenoscopy.