Factors associated with incomplete colonoscopy at a Japanese academic hospital

Table 1 Baseline characteristics of the Japanese population n (%)

Variables	Total (n = 11812)	Cecal intubation
		Incomplete (n = 590)	Complete (n = 11222)
Age (mean ± SD)	57.8 ± 14.8	60.8 ± 15.6	57.6 ± 14.7
Age ≥ 60 yr	6174 (52.3)	358 (60.7)	5816 (51.8)
Sex (female)	4126 (34.9)	248 (42.2)	3878 (34.6)
Poor bowel cleansing	593 (5.0)	107 (18.1)	486 (4.3)
History of abdominal or pelvic surgery	2417 (20.5)	175 (29.7)	2242 (20.0)
Melanosis coli	438 (3.7)	25 (4.2)	413 (3.7)
Inflammatory bowel disease	1199 (10.2)	70 (11.9)	1129 (10.1)

Table 2 Characteristics of male and female patients n (%)

Variables	Male (n = 7686)	Female (n = 4126)	P value1
Age (mean ± SD)	58.2 ± 14.3	57.0 ± 28.7	0.0141
Poor bowel cleansing	353 (4.6)	240 (5.8)	0.0041
History of abdominal or pelvic surgery	1231 (16)	1186 (28.7)	< 0.0001
Melanosis coli	179 (2.3)	259 (6.6)	< 0.0001
Inflammatory bowel disease	753 (9.8)	446 (10.8)	0.0845

¹Mann-Whitney U-test (for age) or Fisher's exact test (for others).

Table 3 Age- and sex-adjusted and multivariable-adjusted analysis for complete cecal intubation rate

	n	Complete rate	P value1	Age- and sex-adjusted2			Multivariable-adjusted3
				OR	95%CI	P value	OR	95%CI	P value
Total	11812	95.0%
Sex
Male	7686	95.6%		1.00			1.00
Female	4126	94.0%	< 0.0001	1.38	1.17-1.64	0.0002	1.20	1.01-1.43	0.0377
Age (yr)
< 60	5638	95.9%		1.00			1.00
≥ 60	6174	94.2%	< 0.0001	1.44	1.22-1.71	< 0.0001	1.48	1.23-1.79	< 0.0001
Poor bowel cleansing
-	11219	95.7%		1.00			1.00
+	593	82.0%	< 0.0001	4.64	3.69-5.84	< 0.0001	4.57	3.62-5.76	< 0.0001
History of abdominal or pelvic surgery
-	9395	95.6%		1.00			1.00
+	2417	92.8%	< 0.0001	1.55	1.28-1.86	< 0.0001	1.65	1.36-1.99	< 0.0001
Melanosis
-	11374	95.0%		1.00
+	438	94.3%	0.5012	0.99	0.65-1.50	0.9503
Inflammatory bowel disease
-	10613	95.1%		1.00			1.00
+	1199	94.2%	0.1617	1.48	1.13-1.95	0.0048	1.45	1.10-1.92	0.0091
Experience of colonoscopist (yr)
< 15	5460	95.04%		1.00
≥ 15	6329	95.0%	0.9324	0.99	0.84-1.17	0.9256

¹Fisher's exact test;

²Age-adjusted for sex; sex-adjusted for age;

³Multivariable-adjusted OR in stepwise logistic regression model, where age and sex were forced to enter into the model; other significant factors were selected from history of abdominal or pelvis surgery, poor bowel preparation, and inflammatory bowel disease with P < 0.05 for entry and removal.

Table 4 Age-adjusted and multivariable-adjusted analysis for complete cecal intubation rate in men

	n	Complete rate	P value1	Age-adjusted2			Multivariable-adjusted3
				OR	95% CI	P value	OR	95% CI	P value
Total	7686	95.6%
Age (yr)
< 60	3625	96.7%		1.00			1.00
≥ 60	4061	94.5%	< 0.0001	1.71	1.36-2.15	< 0.0001	1.74	1.35-2.23	< 0.0001
Poor bowel cleansing
-	7333	96.3%		1.00			1.00
+	353	79.9%	< 0.0001	6.11	4.58-8.17	< 0.0001	5.89	4.39-7.90	< 0.0001
History of abdominal or pelvic surgery
-	6455	95.9%		1.00			1.00
+	1231	93.7%	0.0015	1.44	1.10-1.87	0.0073	1.51	1.15-1.99	0.003
Melanosis coli
-	7507	95.6%		1.00
+	179	93.9%	0.2674	1.23	0.66-2.29	0.5222	NS
Inflammatory bowel disease
-	6933	95.6%		1.00			1.00
+	753	94.7%	0.2263	1.69	1.18-2.43	0.0045	1.57	1.08-2.28	0.017
Experience of colonoscopist (yr)
< 15	3662	95.6%		1.00
≥ 15	4009	95.6%	0.9557	0.98	0.79-1.22	0.8348	NS

¹Fisher's exact test;

²Age-adjusted for sex; sex-adjusted for age;

³Multivariable-adjusted OR in stepwise logistic regression model, where age and sex were forced to enter into the model; other significant factors were selected from history of abdominal or pelvis surgery, poor bowel preparation, and inflammatory bowel disease with P < 0.05 for entry and removal. -: Not entered into the model to avoid multicollinearity; NS: Not selected.

Table 5 Age-adjusted and multivariable-adjusted analysis for complete cecal intubation rate in women

	n	Complete rate	P value1	Age-adjusted2			Multivariable-adjusted3
				OR	95%CI	P value	OR	95%CI	P value
Total	4126	94.0%
Age (yr)
< 60	2013	94.4%		1.00			1
≥ 60	2113	93.6%	0.3257	1.15	0.89-1.49	0.2951	1.13	0.87-1.48	0.3558
Poor bowel cleansing
-	3886	94.5%		1.00			1
+	240	85.0%	< 0.0001	3.03	2.07-4.44	< 0.0001	3.09	2.11-4.54	< 0.0001
History of abdominal or pelvic surgery
-	2940	94.9%		1.00			1
+	1186	91.7%	0.0002	1.66	1.27-2.16	0.0002	1.71	1.31-2.24	< 0.0001
Melanosis coli
-	3867	94.0%		1.00
+	259	94.6%	0.7872	0.86	0.50-1.51	0.6052	NS
Inflammatory bowel disease
-	3680	94.1%		1.00
+	446	93.3%	0.5262	1.25	0.82-1.90	0.2964	NS
Experience of colonoscopist (yr)
< 15	1798	94.0%		1.00
≥ 15	2320	94.0%	1	1.01	0.78-1.30	0.9653	NS

¹Fisher's exact test;

²Age-adjusted for sex; sex-adjusted for age;

³Multivariable-adjusted OR in stepwise logistic regression model, where age and sex were forced to enter into the model; other significant factors were selected from history of abdominal or pelvis surgery, poor bowel preparation, and inflammatory bowel disease with P < 0.05 for entry and removal. -: Not entered into the model to avoid multicollinearity; NS: Not selected.