Assessment of perianal fistulizing Crohn’s disease activity with endoanal ultrasound: A retrospective cohort study

Table 1 Population baseline and clinical characteristics among three groups

Variables	Group 1 (n = 23)	Group 2 (n = 19)	Group 3 (n = 25)	Statistics	P value
Age [M (P25, P75), years]	34.0 (24.0, 43.0)	30.0 (22.0, 38.0)	28.0 (20.5, 37)	H = 2.194	0.334
Sex, n (%)
Male	13 (56.5)	12 (63.2)	18 (72.0)	χ2 = 1.260	0.532
Female	10 (43.5)	7 (36.8)	7 (28.0)
Perianal fistula duration [M (P25, P75), years]	0 (0, 0), (1)	3.0 (1.0, 4.0) (2)	2.0 (0.1, 4.0) (2)	H = 21.475	< 0.0011
Surgical history of perianal fistula, n (%)
Yes	2 (8.7) (1)	12 (63.2) (2)	10 (40.0) (2)	χ2 = 13.727	0.0011
No	21 (91.3)	7 (36.8)	15 (60.0)
Rectal involvement, n (%)
Yes	5 (21.7) (1)	5 (26.3) (1), (2)	15 (60.0) (2)	χ2 = 8.869	0.0121
No	18 (78.3)	14 (73.7)	10 (40.0)
Disease behavior, n (%)
B1	14 (60.9)	12 (63.2)	15 (60.0)	χ2 = 0.047	0.977
B2/B3/B2 + B3	9 (39.1)	7 (36.8)	10 (40.0)
Drug therapy, n (%)
No	6 (26.1)	6 (31.6)	15 (60.0)	χ2 = 7.312	0.115
Biologics	12 (52.2)	11 (57.9)	7 (28.0)
Others	5 (21.7)	2 (10.5)	3 (12.0)
Literacy level, n (%)
Junior high school education or below	7 (30.4)	3 (15.8)	7 (28.0)	χ2 = 7.956	0.093
High school education	13 (56.5)	11 (57.9)	7 (28.0)
Bachelor degree or above	3 (13.0)	5 (26.3)	11 (44.0)

¹A statistically significant difference within different categories of a group (P < 0.05).

For pairwise comparison within a group, different superscript letters (1,2) represent statistical differences between different categories, that is, P (1, 2) < 0.05, P (1, 1) > 0.05, P (2, 2) > 0.05.

Table 2 Serum C-reactive protein and fecal calprotectin among three groups

Variables	Group 1 (n = 23)	Group 2 (n = 19)	Group 3 (n = 25)	Value	P value
CRP [M (P25, P75), mg/L]	5.17 (2.20, 14.6)	4.84 (3.28, 23.29)	13.5 (4.02,27.75)	H = 3.832	0.147
CRP (new) [M (P25, P75), mg/L]1	5.9 (2.3, 13.9)	6.03 (3.3, 17.935)	13.5 (4.02,27.75)	H = 3.532	0.171
Fecal calprotectin2 [n (%), ug/g]
< 60	3 (13.6) (1)	2 (11.8) (1)	16 (64.0) (2)	χ2 = 24.060	< 0.001a
60-500	13 (59.1) (1)	13 (76.5) (1)	3 (12.0) (2)
> 500	6 (27.3) (1)	2 (11.8) (1)	6 (24.0) (2)

^aP < 0.05, a statistically significant difference within different categories of a group.

¹C-reactive protein (new) was chosen because an interpolation method was utilized to process missing data for a missing C-reactive protein value in group 1 and 2.

²Group 1 and Group 2 are each missing one value and two values, respectively.

For pairwise comparison within a group, different superscript letters (1,2) represent statistical differences between different categories, that is, P (1, 2) < 0.05, P (1, 1) > 0.05. CRP: C-reactive protein.

Table 3 Comparison of Crohn's disease activity index, perianal disease activity index scores among three groups, M (P25, P75)

Variables	Group 1 (n = 23)	Group 2 (n = 19)	Group 3 (n = 25)	Value	P value
CDAI	76.5 (56, 174.3) (1)	103 (44, 203) (1)	187 (137, 254.5) (2)	H = 12.893	0.002a
PDAI	1 (0, 2) (1)	1 (1, 4) (1)	6 (5, 7.5) (2)	H = 49.006	0.000a

^aP < 0.05, A statistically significant difference within different categories of a group.

For pairwise comparison within a group, different superscript letters (1,2) represent statistical differences between different categories, that is, P (1, 2) < 0.05, P (1, 1) > 0.05. PDAI: Perianal disease activity index; CDAI: Crohn's disease activity index.

Table 4 Classification of Fistulas between magnetic resonance and endoanal ultrasound

EUS diagnosis	MR diagnosis		Kappa	P value
	Simple fistulas	Complex fistulas
Simple fistulas	13	4	0.752	0.000
Complex fistulas	1	26

EUS: Endoanal ultrasound; MR: Magnetic resonance.

Table 5 Comparison of SWV, Limberg grade of anal fistula blood flow between magnetic resonance and endoanal ultrasound

Variables	Group 2 (n = 19)	Group 3 (n = 25)	Value	P value
Shear wave velocity, m/S	2.70 ± 0.52 m/S	2.30 ± 0.57	t = 2.467	0.018
Limberg grade
Level 0	11	4	χ2 = 8.903	0.012
Level 1	5	8
Level 2 or above	5	16