Predictors for difficult cecal insertion in colonoscopy: The impact of obesity indices

Table 1 Baseline characteristics of study participants n (%)

Baseline characteristics (n = 1678)
Age (yr) (mean ± SD)	50.42 ± 9.93
< 65	1518 (90.5)
≥ 65	160 (9.5)
Gender
Male/female	1012 (60.3)/666 (39.7)
Obesity indices (mean ± SD)
BMI (kg/m2)	23.92 ± 2.96
WHR (n =1674)	0.90 ± 0.08
WC (cm) (n =1676)	86.95 ± 8.03
VAT volume (cm3)	905.29 ± 475.22
SAT volume (cm3)	1707.72 ± 576.55
History of abdominal surgery
Gynecological surgery	231 (13.8)
Gastrectomy	163 (9.7)
Other abdominal surgery	5 (0.3)
Constipation
Yes/no	182 (10.8)/1496 (89.2)
Experience
Attending physicians/Fellow	1039 (61.9)/639 (38.1)
Bowel preparation
Excellent to fair/Poor to inadequate	1209 (72.1)/469 (27.9)
Diverticulosis on colonoscopy
Yes/no	95 (5.7)/1583 (94.3)
CIT (min)
Median CIT (range)	7 (2-56) (IQR, 5-10)
Mean CIT (SD)1	8.58 ± 5.29
≤ 10 min	1278 (76.2)
> 10 min	400 (23.8)

¹One hundred thirty one patients were undergone multiple surgeries and duplicated with other type operation. BMI: Body mass index; WHR: Waist-to-hip circumference ratio; WC: Waist circumference; VAT: Visceral adipose tissue; SAT: Subcutaneous adipose tissue; CIT: Cecal insertion time.

Table 2 Cecal insertion time according to study variables, with odd ratios estimated by multivariable logistic regression analysis n (%)

	Cecal insertion time (min)		P value	Multivariate logistic regression analysis	P value
	≤ 10 (n = 1278)	> 10 (n = 400)		OR (95%CI)
Age (yr)			0.125
< 65	1164 (76.7)	354 (23.3)
≥ 65	114 (71.3)	46 (28.7)
Gender			0.001
Male	800 (79.1)	212 (20.9)		Ref	0.047
Female	478 (71.8)	188 (28.2)		1.29 (1.00-1.67)
Obesity indices
BMI (kg/m2)			< 0.001
< 23	457 (72.2)	176 (27.8)a		1.62 (1.16-2.25)	0.004
23-24.9	388 (83.6)	76 (16.4)b		Ref
≥ 25	433 (74.5)	148 (25.5)		1.80 (1.31-2.49)	< 0.001
WHR (n = 1674)			0.060
Normal (≤ 0.9 for men, ≤ 0.8 for women)	257 (72.4)	98 (27.6)
High	1018 (77.2)	301 (22.8)
WC (cm) (n = 1676)			0.316
Normal (≤ 102 cm for men, ≤ 88 cm for women)	1098 (76.6)	335 (23.4)
High	179 (73.7)	64 (26.3)
VAT volume (cm3)			< 0.001
< 500	237 (68.3)	110 (31.7)c		1.50 (1.09-2.07)	0.013
500-1499	906 (78.9)	242 (21.1)		Ref
≥ 1500	135 (73.8)	48 (26.2)		1.27 (0.86-1.88)	0.223
SAT volume (cm3)			0.848
< 1000	107 (78.1)	30 (21.9)
1000-1999	831 (75.9)	264 (24.1)
≥ 2000	340 (76.2)	106 (23.8)
History of abdominal surgery			0.626
No	1077 (76.4)	333 (23.6)
Yes	201 (75.0)	67 (25.0)
Constipation			0.112
No	1148 (76.7)	348 (23.3)
Yes	130 (71.4)	52 (28.6)
Experience			< 0.001
Attending physicians	833 (80.2)	206 (19.8)		Ref
Fellow	445 (69.6)	194 (30.4)		1.73 (1.38-2.19)	< 0.001
Bowel preparation			0.919
Excellent to fair	920 (76.1)	289 (23.9)
Poor to inadequate	358 (76.3)	111 (23.7)
Diverticulosis			0.099
No	1199 (75.7)	384 (24.3)
Yes	79 (83.2)	16 (16.8)

^aP < 0.001 vs BMI 23-24.9 kg/m²,

^bP < 0.001 vs BMI ≥ 25 kg/m²,

^cP < 0.001 vs VAT volume 500-1499 cm³. BMI: Body mass index; WHR: Waist-to-hip circumference ratio; WC: Waist circumference; VAT: Visceral adipose tissue; SAT: Subcutaneous adipose tissue.

Table 3 Cecal insertion time according to study variables, by gender, with P values estimated by univariable analysis n (%)

	Male (n = 1012)			Female (n = 666)
	Cecal insertion time (min)		P value	Cecal insertion time (min)		P value
	≤ 10 (n = 800)	> 10 (n = 212)		≤ 10 (n = 478)	> 10 (n = 188)
Age (yr)			0.089			0.619
< 65	726 (90.8)	184 (86.8)		438 (91.6)	170 (90.4)
≥ 65	74 (9.3)	28 (13.2)		40 (8.4)	18 (9.6)
Obesity indices
BMI (kg/m2)			0.007			0.013
< 23	202 (25.3)	58 (27.4)		255 (53.3)	118 (62.8)b
23-24.9	261 (32.6)	46 (21.7)a		127 (26.6)	30 (16.0)
≥ 25	337 (42.1)	108 (50.9)		96 (20.1)	40 (21.3)
WHR			0.414			0.332
Normal	118 (14.8)	36 (17.1)		139 (29.1)	62 (33.0)
High	680 (85.2)	175 (82.9)		338 (70.9)	126 (67.0)
WC (cm)			0.396			0.508
Normal	768 (96.1)	201 (94.8)		330 (69.0)	134 (71.7)
High	31 (3.9)	11 (5.2)		148 (31.0)	53 (28.3)
VAT volume (cm3)			0.123			0.020
< 500	73 (9.1)	24 (11.3)		164 (34.3)	86 (45.7)c
500-1499	606 (75.8)	146 (68.9)		300 (62.8)	96 (51.1)
≥ 1500	121 (15.1)	42 (19.8)		14 (2.9)	6 (3.2)
SAT volume (cm3)			0.511			0.082
< 1000	90 (11.3)	23 (10.8)		17 (3.6)	7 (3.7)
1000-1999	575 (71.9)	146 (68.9)		256 (53.6)	118 (62.8)
≥ 2000	135 (16.9)	43 (20.3)		205 (42.9)	63 (33.5)
History of abdominal surgery			0.087			0.213
No	687 (85.9)	172 (81.1)		390 (81.6)	161 (85.6)
Yes	113 (14.1)	40 (18.9)		88 (18.4)	27 (14.4)
Constipation			0.480			0.350
No	740 (92.5)	193 (91.0)		408 (85.4)	155 (82.4)
Yes	60 (7.5)	19 (9.0)		70 (14.6)	33 (17.6)
Experience			< 0.001			0.015
Attending physicians	552 (69.0)	115 (54.2)		281 (58.8)	91 (48.4)
Fellow	248 (31.0)	97 (45.8)		197 (41.2)	97 (51.6)
Bowel preparation			0.561			0.462
Excellent to fair	561 (70.1)	153 (72.2)		359 (75.1)	136 (72.3)
Poor to inadequate	239 (29.9)	59 (27.8)		119 (24.9)	52 (27.7)
Diverticulosis			0.135			0.966
No	734 (91.8)	201 (94.8)		465 (97.3)	183 (97.3)
Yes	66 (8.3)	11 (5.2)		13 (2.7)	5 (2.7)

WHR: male n = 1009, female n = 665; WC: male n = 1011, female n = 665.

^aP = 0.004 vs BMI ≥ 25 kg/m²,

^bP = 0.009 vs BMI 23-24.9 kg/m²,

^cP = 0.015 vs VAT volume 500-1499 cm³. BMI: Body mass index; WHR: Waist-to-hip circumference ratio; WC: Waist circumference; VAT: Visceral adipose tissue; SAT: Subcutaneous adipose tissue.

Table 4 Predictive parameters of prolonged cecal insertion time according to gender by multivariable logistic regression analysis when body mass index and visceral adipose tissue volume were considered simultaneously or separately

		OR	95%CI	P value	OR	95%CI	P value	OR	95%CI	P value
Male	BMI (kg/m2)
	< 23	1.58	1.00-2.50	0.049	1.69	1.10-2.60	0.017
	23-24.9	Ref			Ref
	≥ 25	1.82	1.22-2.71	0.003	1.88	1.28-2.75	0.001
	VAT volume (cm3)
	< 500	1.40	0.80-2.43	0.236				1.41	0.86-2.33	0.178
	500-1499	Ref						Ref
	≥ 1500	1.24	0.81-1.90	0.323				1.42	0.96-2.12	0.082
	Experience
	Attending physicians	Ref			Ref			Ref
	Fellow	1.93	1.41-2.63	< 0.001	1.92	1.41-2.63	< 0.001	1.88	1.38-2.57	< 0.001
Female	BMI (kg/m2)
	< 23	1.66	1.02-2.69	0.041	1.96	1.25-3.10	0.004
	23-24.9	Ref			Ref
	≥ 25	1.79	1.02-3.13	0.042	1.71	0.99-2.96	0.053
	VAT volume (cm3)
	< 500	1.54	1.03-2.31	0.034				1.66	1.17-2.35	0.005
	500-1499	Ref						Ref
	≥ 1500	1.31	0.47-3.64	0.606				1.47	0.55-3.96	0.446
	Experience
	Attending physicians	Ref			Ref			Ref
	Fellow	1.53	1.08-2.16	0.016	1.52	1.08-2.14	0.016	1.54	1.10-2.17	0.013

BMI: Body mass index; VAT: Visceral adipose tissue.