Table 1.
Baseline characteristics of patients at start infliximab treatment
| Total, n = 215 | YP start IFX < 10 years of age, n = 110 | OP start IFX ≥ 10 years of age, n = 105 | p value | |||
|---|---|---|---|---|---|---|
| Age at diagnosis in years (IQR) | 9.22 (6.6–12.9) | 6.71 (5.12–8.36) | 12.93 (11.65–14.55) | < 0.001 | ||
| Age at start treatment in years (IQR) | 9.72 (8.26–14.0) | 8.32 (6.95–8.93) | 14.32 (12.79–15.61) | < 0.001 | ||
| Sex (%) | Male | 122 (57%) | 58 (53%) | 64 (61%) | 0.224 | |
| BSA (IQR) | n = 171 | 1.53 (0.90–1.48) | 0.90 (0.78–1.02). | 1.52 (1.29–1.69) | < 0.001 | |
| Diagnosis (%) | Crohn’s disease | 147 (69%) | 66 (60%) | 81 (77%) | 0.024 | |
| Ulcerative colitis | 50 (23%) | 33 (30%) | 17 (16%) | |||
| IBD unclassified | 18 (8%) | 11 (10%) | 7 (7%) | |||
| Ethnicity (%) | Afro-Caribbean | 19 (9%) | 8 (7%) | 10 (10%) | 0.388 | |
| Arab | 33 (15%) | 14 (12.8%) | 19 (18%) | |||
| Asian | 1 (1%) | 1 (0.9%) | 0 (0%) | |||
| Caucasian | 149 (70%) | 79 (73%) | 72 (69%) | |||
| Other | 11 (5%) | 8 (7.3%) | 3 (3%) | |||
| TPMT status (%) | Homozygous | 78 (36%) | 46 (42%) | 32 (30%) | 0.295 | |
| Heterozygous | 11 (5%) | 4 (4%) | 7 (7%) | |||
| Unknown | 126 (59%) | 60 (54%) | 66 (63%) | |||
| ESR (mm/h) (IQR) | n = 161 | 28 (19–42) | 30 (20–42) | 27 (16–49) | 0.654 | |
| CRP (mg/L) (IQR) | n = 180 | 11 (3.4–40.5) | 10 (3–25) | 20 (4–52) | 0.066 | |
| Albumin (g/L) (IQR) | n = 177 | 37 (33–42) | 35 (31.2–39.6) | 40 (34–43) | 0.095 | |
| Clinical disease activity (%) | Quiescent 0 | 4 (2%) | 3 (3%) | 1 (1%) | 0.659 | |
| Mild 1 | 15 (11%) | 11 (13%) | 8 (12%) | |||
| Moderate 2 | 80 (37%) | 41 (48%) | 38 (47%) | |||
| Severe 3 | 65 (30%) | 31 (36%) | 34 (42%) | |||
| Median start dose (mg/kg) (IQR) | 5 (5–5) | 5 (5–5) | 5 (5–5) | 0.015 | ||
| Paris classification | Age | A1a | 115 (54%) | 110 (100%) | 5 (5%) | < 0.001 |
| A1b | 100 (46%) | 100 (95%) | ||||
| For CD patients | Location | L1 | 15 (13%) | 7 (14%) | 8 (11%) | 0.071 |
| L2 | 37 (31%) | 21 (43%) | 16 (23%) | |||
| L3 | 68 (56%) | 21 (43%) | 45 (65%) | |||
| L4a | 31 (26%) | 14 (21%) | 17 (21%) | |||
| L4b | 5 (4%) | 3 (5%) | 2 (3%) | |||
| Behaviour | B1 | 100 (83%) | 38 (76%) | 60 (87%) | 0.126 | |
| B2 | 11 (9%) | 5 (10%) | 6 (9%) | |||
| B3 | 7 (5%) | 6 (12%) | 1 (1%) | |||
| B2B3 | 3 (2%) | 1 (2%) | 2 (3%) | |||
| Perianal disease (%) | 43 (36%) | 22 (43%) | 21 (31%) | |||
| Growth delay (%) | 43 (37%) | 19 (37%) | 24 (36%) | |||
| For UC and IBD-U patients | Extent | 1 | 1 (2%) | – | 1 (5%) | 0.747 |
| 2 | 4 (9%) | 2 (9%) | 2 (8%) | |||
| 3 | 5 (11%) | 3 (14%) | 2 (8%) | |||
| 4 | 36 (78%) | 17 (77%) | 19 (79%) | |||
| Ever severe (%) | 38 (83%) | 17 (79%) | 21 (88%) | 0.361 |
p values are from Fisher’s exact test for categorical variables and from Kruskal-Wallis or Mann-Whitney U test for continuous variables. p values < 0.05 were considered as significant
Abbreviations: YP young patients, OP older patients, TPMT thiopurine methyltransferase, ESR erythrocyte sedimentation, CRP C-reactive protein, BSA body surface area, IQR interquartile range, % percentage