Table 1.
Clinical and demographic characteristics of the study cohort stratified by disease behaviour during follow-up
| Inflammatory (B1) (n=835) |
Stricturing (B2) (n=54) |
Penetrating (B3) (n=24) |
|
|---|---|---|---|
| Demographics and follow-up | |||
|
| |||
| Age at diagnosis (years) | 12·3 (9·9 to 14·5) | 12·9 (10·6 to 15·1) | 15·6 (12·9 to 16·4)* |
| Female sex (%) | 316 (38%) | 19 (35%) | 13 (54%) |
| African American or mixed race | 103 (12%) | 9 (17%) | 9 (38%)† |
| Duration of follow-up (months) | 47 (36 to 55) | 41 (36 to 50)‡ | 40 (34 to 49)‡ |
| Time to behaviour change (days) | ·· | 520 (301 to 722) | 497 (260 to 680) |
|
| |||
| Disease activity and treatment exposures | |||
|
| |||
| Moderate-to-severe disease activity | 388 (46%) | 23 (43%) | 12 (50%) |
| Height Z-score | −0·25 (−0·94 to 0·45) | −0·6 (−1·34 to 0·09) | −0·35 (−1·23 to 0·33) |
| BMI Z-score | −0·66 (−1·63 to 0·15) | −0·85 (−1·88 to 0·26) | −0·76 (−1·84 to 0·18) |
| Anti-TNFα within 90 days of diagnosis | 173 (21%) | 14 (26%) | 4 (17%) |
| Immunomodulator within 90 days | 378 (45%) | 21 (39%) | 14 (58%) |
| Small bowel imaging within 6 months | 608 (73%) | 47 (87%)‡ | 19 (79%) |
|
| |||
| Disease location at diagnosis | |||
|
| |||
| Isolated terminal ileum with or without caecum involvement | 166 (20%) | 16 (30%) | 7 (29%) |
| Isolated colonic | 210 (25%) | 10 (19%) | 3 (13%) |
| Ileo-colonic | 459 (55%) | 28 (52%) | 14 (58%) |
| Perianal | 115 (14%) | 7 (13%) | 4 (17%) |
|
| |||
| Serological reactivity status at diagnosis | |||
|
| |||
| ASCA IgA | 182 (22%) | 22 (41%)† | 14 (58%)* |
| ASCA IgG | 182 (22%) | 19 (35%)‡ | 9 (38%) |
| CBir1 | 293 (35%) | 32 (59%)* | 16 (67%)† |
| Granulocyte–macrophage colony-stimulating factor autoantibody | 381 (46%) | 35 (65%)† | 14 (58%) |
| Outer membrane protein C precursor | 54 (6%) | 4 (7%) | 2 (8%) |
| Perinuclear anti-neutrophil cytoplasmic antibodies | 129 (15%) | 5 (9%) | 3 (13%) |
In the Montreal classification of disease behaviour, B1 corresponds to inflammatory behaviour with no stricturing or luminal penetrating complications, B2 to stricturing behaviour with no luminal penetrating complications, and B3 to luminal penetrating behaviour with or without concurrent stricturing complications.
BMI=body-mass index. TNFα=tumour necrosis factor α. ASCA=anti-Saccharomyces cerevisiae antibodies.
p value <0·001 for comparisons of B2 vs B1 and B3 vs B1.
p value <0·01 for comparisons of B2 vs B1 and B3 vs B1.
p value <0·05 for comparisons of B2 vs B1 and B3 vs B1. A version of this table with exact p values is included in the appendix.