Assessing disease activity using the pediatric Crohn’s disease activity index: Can we use subjective or objective parameters alone?

Table 1 Descriptive statistics

	Registry (n = 4141)		REACH (n = 1011)		IMAgINE (n = 1881)
	Range	Median (IQR)	Range	Median (IQR)	Range	Median (IQR)
Age at baseline	1.5-16.1	12.2 (3.6)	6.0-17.8	13.8 (3.2)	6-17.0	14.0 (4.0)
Age at diagnosis	1.5-15.9	12.2 (3.6)	4.8-16.6	11.8 (4.1)	2.4-16.4	10.6 (3.2)
Gender (female), n (%)	180 (43.5)		40 (39.6)		82 (43.6)
	Range	mean ± SD	Range	mean ± SD	Range	mean ± SD
PCDAI BL	0-82.5	31.39 ± 15.34	25-62.5	41.14 ± 8.18	7.5-62.5	40.97 ± 7.48
PCDAI Q1	0-52.5	10.25 ± 9.75	0-40	9.77 ± 8.55	0-57.5	16.78 ± 12.64
PCDAI Q4	0-50.0	8.58 ± 9.21	0-70	12.07 ± 14.10	0-70	19.56 ± 16.34

¹The baseline characteristics describe participants with full pediatric Crohn’s disease activity index (PCDAI) data (i.e. had individual PCDAI scores collected) at baseline. Q1 PCDAI scores describe participants with full baseline and Q1 PCDAI data available (n = 414, 97, and 159 participants for the Registry, REACH, and IMAgINE datasets respectively). Q4 PCDAI scores describe participants with full baseline and Q1 PCDAI data available (n = 216, 75, and 183 participants for the Registry, REACH, and IMAgINE datasets respectively). PCDAI: Pediatric Crohn’s disease activity index.

Table 2 Linear regression analysis examining the contribution of pediatric Crohn’s disease activity index change scores to Q1 and Q4 pediatric Crohn’s disease activity index disease activity

	PCDAI∆ Q1 to BL (n = 670)
	Full scale	Subjective	Objective	Composite
	β values	β values	β values	β values
1. Abdominal pain	0.57b	0.80b		0.65b
2. Stooling	0.42b	0.53b		0.45b
3. Well-being	0.13
4. HCT	-0.09
5. ESR	0.94b		1.27b	0.96b
6. Albumin	0.46b		0.41b	0.45b
7. Weight	0.30b		0.52b	0.32b
8. Height Velocity	0.50b		0.56b	0.48b
9. Abdominal exam	0.08
10. Perirectal exam	0.47b		0.45a	0.48b
11. Extraintestinal	0.13
R2	0.32	0.18	0.21	0.32
	PCDAI∆ Q4 to BL (n = 474)
1. Abdominal Pain	0.45b	0.65b		0.45b
2. Stooling	0.42a	0.52b		0.42a
3. Well-being	0.58b	0.87b		0.58b
4. HCT	-0.01
5. ESR	1.32b		1.56b	1.32b
6. Albumin	0.81b		0.84b	0.81b
7. Weight	0.49b		0.63b	0.49b
8. Height velocity	0.45b		0.48b	0.45b
9. Abdominal exam	0.35a		0.83b	0.35a
10. Perirectal exam	0.78b		0.90b	0.78b
11. Extraintestinal	0.42a		0.67a	0.42b
R2	0.45	0.22	0.36	0.45

^aP < 0.05.

^bP ≤ 0.001. PCDAI: Pediatric Crohn’s disease activity index; HCT: Hematopoietic cell transplantation; ESR: Erythrocyte sedimentation rate.

Table 3 Correct and incorrect identification of remitters and non-remitters

	Subjective-remission status		Objective-remission status
Full PCDAI-remission status	Remitters	Non-remitters	Remitters	Non-remitters
	n (%)	n (%)	n (%)	n (%)
Remitters at Q1 (n = 397)	292 (73.8)	105 (26.2)	284 (71.5)	113 (28.5)
Non-remitters at Q1 (n = 273)	46 (16.7)	227 (83.3)	58 (21.2)	215 (78.8)
Remitters at Q4 (n = 274)	202 (73.7)	72 (26.3)	204 (74.5)	70 (25.3)
Non-remitters at Q4 (n = 200)	45 (22.5)	155 (77.5)	56 (28.0)	144 (72.0)

Subjective subscale is composed of abdominal pain and stooling; Objective subscale is composed of erythrocyte sedimentation rate, albumin, weight, height velocity, and perirectal examination. Shaded cells = number of patients that would be incorrectly (or differently) classified as having active or inactive disease based on the subjective components alone (e.g., At the Q1 time point, 397 patients were classified as being in remission, but based on the subjective only scoring, 292 (73.8%) of those patients would be classified as being in remission, while the other 26% would be classified as having active disease). PCDAI: Pediatric Crohn’s disease activity index.