Table 1.

Patient and disease characteristics at diagnosis of the paediatric Crohn’s disease study population, stratified by early anti-TNF use

Characteristics	Early anti-TNF therapy [n = 135; 59%]	No early anti-TNF therapy [n = 196; 41%]	Total [n = 331]	p-value
Age in years, median [IQR]	13.9 [12.2–15.3]	13.2 [10.8–15.1]	13.7 [11.4–15.2]	0.03
Male sex, n [%]	88 [65]	116 [59]	204 [62]	0.32
First-degree relative with IBD, n [%]	23 [17]	42 [21]	65 [20]	0.40
Ethnicity, n [%]				0.73
White	87 [73]	120 [67]	207 [70]
Asian	15 [13]	23 [13]	38 [13]
Black	3 [3]	5 [3]	8 [3]
Hispanic/Latino	1 [1]	1 [1]	2 [1]
Mixed/other	13 [11]	29 [16]	42 [14]
Time to diagnosis in days, median [IQR]	141 [76–365]	159 [83–250]	153 [79–285]	0.85
BMI Z-score, mean [SD]	-1.21 [1.48]	-0.79 [1.50]	-0.96 [1.51]	0.013
Disease location,an [%]				<0.001
L1 isolated ileal	21 [15]	61 [32]	82 [25]
L2 isolated colonic	16 [12]	40 [21]	56 [17]
L3 ileocolonic	95 [71]	85 [45]	180 [56]
L4 isolated upper disease	2 [2]	3 [2]	5 [2]
Upper gastrointestinal tract involvementa, n [%]				0.33
L4a	61 [45]	84 [44]	145 [45]
L4b	12 [9]	10 [5]	22 [7]
L4ab	0 [0]	3 [2]	3 [1]
No upper disease	62 [46]	92 [49]	154 [48]
Perianal disease,an [%]	46 [34]	19 [10]	65 [20]	<0.001
Disease behaviour,an [%]				0.21
B1	112 [83]	174 [89]	286 [87]
B2	12 [9]	15 [8]	27 [8]
B3	9 [7]	5 [3]	14 [4]
B2B3	2 [2]	1 [1]	3 [1]
Disease activity, n [%]				0.006
None/inactive	4 [3]	11 [6]	15 [5]
Mild	27 [20]	67 [35]	94 [29]
Moderate	51 [38]	66 [34]	117 [36]
Severe	52 [39]	48 [25]	100 [31]
Moderate-to-severe disease activity, n [%]	103 [77]	114 [59]	217 [67]	0.002
wPCDAI, mean [SD]	51 [22]	44 [21]	47 [21]	0.005
Endoscopic severity,bn [%]				0.13
Mucosal healing	3 [3]	8 [6]	11 [5]
Mild endoscopic inflammation	15 [17]	38 [27]	53 [23]
Moderate-to-severe endoscopic inflammation	73 [80]	897 [68]	170 [73]
SES-CD score, median [IQR]	12 [7–18]	15 [11–22]	13 [8–19]	0.009
Induction therapy, n [%]				<0.001
Exclusive Enteral Nutrition	47 [35]	136 [69]	183 [55]
Corticosteroids	19 [14]	41 [21]	60 [18]
5-aminosalicylates	1 [1]	9 [5]	10 [3]
Upfront anti-TNFc	64 [47]	n/a	64 [19]
None/otherd	4 [3]	10 [5]	14 [4]
Steroid use within first 3 months, n [%]	35 [26]	74 [38]	109 [33]	0.024
IMM use within first 3 months, n [%]	110 [82]	128 [65]	238 [72]	<0.001

Missing values for each variable: age in years 0; male sex 0; first-degree relative with IBD 0; ethnicity 34; days to diagnosis 12; BMI Z-score 12; disease location 8; upper gastrointestinal tract involvement 7; perianal disease 10; disease behaviour 1; disease activity 5; wPCDAI 77; endoscopic severity 97; SES-CD score 97; induction therapy 0; steroid use within first 3 months 1; IMM use within first 3 months 1.

SES-CD, Simple Endoscopic Score for Crohn’s disease; anti-TNF: anti-tumour necrosis factor alpha; IMM: immunomodulator [methotrexate, azathioprine, 6-mercaptopurine, thioguanine]; IQR: interquartile range; SD: standard deviation; wPCDAI: weighted paediatric Crohn's disease activity index.

^aAs per Paris classification.

^bBased on SES-CD reference values according to MINI-index paper.

^cMost [n = 41] of these patients had one or more clear indications to start upfront anti-TNF, including active perianal disease [n = 19], B2/B3 disease at diagnosis [n = 18], inclusion in the TISKids trial [n = 7], active EIMs [n = 8]. Patients with upfront anti-TNF could also have one or multiple predictors of poor outcome, such as growth delay [n = 13], extensive disease [n = 30], deep colonic ulcer [n = 22]. Three patients did not have any predictor of poor outcome or other clear indication for upfront anti-TNF.

^dFive dietary therapy [Crohn’s disease exclusion diet with partial enteral nutrition], three antibiotics, three monotherapy with an immunomodulator, two no therapy, one unknown.