Withdrawal time in excellent or very poor bowel preparation qualities

Table 1 Criteria used to classify bowel preparation quality

Bowel preparation quality	Criteria
Excellent	Mucosal detail clearly visible without washing (suctioning of liquid allowed
Good	Minimal turbid fluid in colonic segments and entire mucosa well seen after cleaning
Fair	There is minor residual material in the colonic segments. Necessary to suction liquid to adequately view the colonic segments
Poor	Necessary to wash and suction to obtain a reasonable view. Portion of mucosa in colonic segments seen after cleaning but up to 15% of the mucosa not seen because of retained material
Unsatisfactory	Solid stool not cleared with washing and suctioning. More than 15% of the mucosa not seen

Table 2 Patient characteristics based on bowel preparation quality n (%)

Characteristics	Quality of bowel preparation
	Excellent (n = 108)	Good (n = 4051)	Fair (n = 2889)	Poor (n = 1045)	Unsatisfactory (n = 238)
Mean age ± SD, yr	58 ± 7.6	59 ± 7.6	59 ± 7.9	60 ± 7.7	59 ± 8.3
Women	65 (60)	2481 (61)	1596 (55)	537 (51)	117 (49)
Race
Asian	1 (1)	32 (1)	16 (1)	4 (0)	0 (0)
White	1 (1)	47 (1)	34 (1)	15 (1)	5 (2)
Black	25 (23)	875 (22)	697 (24)	280 (27)	82 (35)
Hispanic	81 (75)	3097 (77)	2142 (74)	746 (71)	151 (63)
Morning procedure	45 (42)	1877 (46)	1212 (42)	428 (41)	78 (33)

Table 3 Withdrawal time and polyp detection based on bowel preparation quality n (%)

	Quality of bowel preparation					P-value
	Excellent (n = 108)	Good (n = 4051)	Fair (n = 2889)	Poor (n = 1045)	Unsatisfactory (n = 238)
Mean duration of colonoscope withdrawal ± SD, min	10 ± 5.5	12 ± 5.3	13 ± 5.9	12 ± 5.2	11 ± 9.4	< 0.001
No. of colonic segments with polyps						< 0.001
0	85 (77)	2707 (67)	1799 (62)	703 (67)	181 (76)
1	17 (16)	769 (19)	581 (20)	223 (21)	38 (16)
2	3 (3)	375 (9)	305 (11)	74 (7)	13 (6)
3	1 (1)	136 (3)	145 (5)	31 (3)	6 (3)
4	2 (2)	43 (1)	38 (1)	11 (1)	0 (0)
5	0 (0)	16 (0)	18 (1)	3 (0)	0 (0)
6	0 (0)	2 (0)	3 (0)	0 (0)	0 (0)
7	0 (0)	2 (0)	0 (0)	0 (0)	0 (0)
8	0 (0)	1 (0)	0 (0)	0 (0)	0 (0)
Total No. of colonic polyps						< 0.001
0	85 (77)	2707 (67)	1799 (62)	703 (67)	181 (76)
1	13 (12)	581 (14)	446 (15)	42 (4)	30 (13)
2	2 (2)	231 (6)	164 (6)	60 (6)	8 (3)
3	4 (4)	256 (6)	195 (7)	37 (4)	10 (4)
4	2 (2)	152 (4)	155 (5)	22 (2)	5 (2)
5	1 (1)	73 (2)	90 (3)	6 (1)	4 (2)
> 5	1 (1)	51 (1)	30 (1)	2 (0)	0 (0)

Table 4 Predictors of higher number of colonic segments with polyps and total number of colonic polyps during screening colonoscopy

	No. colonic segment with polyps		Total No. colonic polyps
	OR (95%CI)	P-value	OR (95%CI)	P-value
Older age	1.01 (1.00-1.03)	0.011	1.01 (1.00-1.02)	0.026
Gender of male1	1.31 (1.11-1.55)	0.002	1.18 (1.00-1.39)	0.047
Race
Asian2	0.89 (0.34-2.25)	NS	1.06 (0.41-2.73)	NS
White2	0.69 (0.33-1.45)	NS	0.70 (0.33-1.45)	NS
Black2	1.17 (0.97-1.41)	NS	1.22 (1.01-1.47)	0.041
Later time of colonoscopy	1.00 (1.00-1.00)	NS	1.00 (1.00-1.00)	0.043
Better bowel preparation quality	1.10 (1.00-1.21)	0.04	1.11 (1.01-1.22)	0.030
Longer duration of colonoscope withdrawal	1.14 (1.12-1.16)	< 0.0001	1.14 (1.12-1.16)	< 0.0001
Adenoma detection rate of endoscopist	1.03 (1.02-1.04)	< 0.0001	1.03 (1.02-1.04)	< 0.0001
Duration of colonoscopy practice of endoscopist	0.98 (0.97-0.98)	< 0.0001	0.98(0.97-0.99)	< 0.0001
Involvement of trainee during colonoscopy	0.93 (0.72-1.19)	NS	0.93(0.73-1.19)	NS

¹Compared to gender of female;

²Compared to Hispanic. NS: Not statistically significant.

Table 5 Association between longer withdrawal time and higher polyp detection in various bowel preparation qualities

	No. of colonic segments with polyps		Total No. colonic polyps
	OR (95%CI)1	P-value	OR (95%CI)1	P-value
Excellent	1.07 (0.99-1.26)	NS	1.11 (0.99-1.24)	NS
Good	1.16 (1.13-1.19)	< 0.0001	1.15 (1.13-1.18)	< 0.0001
Fair	1.13 (1.10-1.17)	< 0.0001	1.13 (1.10-1.16)	< 0.0001
Poor	1.18 (1.11-1.26)	< 0.0001	1.20 (1.13-1.29)	< 0.0001
Unsatisfactory/very poor	1.02 (0.99-1.12)	NS	1.05 (0.99-1.10)	NS

¹Adjusted to age, gender, race, timing of colonoscopy, endoscopist adenoma detection rate, duration of colonoscopy practice of endoscopists, involvement of trainee during colonoscopy. NS: Not statistically significant.