Baseline characteristics of the sample (n=100)
| Monotherapy group (n=46) | 6-TGN level between 235 and 450 pmol/8×108 erythrocytes (n=32) | 6-TGN level outside 235–450 pmol/8×108 erythrocytes (n=22) | Whole sample (n=100) | |
| Male sex, n (%) | 22 (47.8) | 19 (59.4) | 12 (54.6) | 53 (53.0) |
| Age, years, median (IQR) | 38 (29, 53) | 34 (28, 41) | 32 (27, 37) | 34 (28, 46) |
| Weight, kg, median (IQR) | 79 (68, 95) | 72 (60, 80) | 73 (65, 82) | 74 (65, 88) |
| Diagnosis of Crohn’s (vs UC and IBD-U), n (%) | 33 (71.7) | 24 (75.0) | 19 (86.4) | 76 (76.0) |
| Disease extent | ||||
| Crohn’s (%) | 33 (71.7) | 24 (75) | 19 (86.4) | 76 (76) |
| Colonic | 10 (21.7) | 5 (15.6) | 7 (31.8) | 22 (22) |
| Ileocolonic | 16 (34.8) | 17 (53.1) | 9 (40.9) | 42 (42) |
| Ileal | 6 (13.0) | 2 (6.3) | 2 (9.1) | 10 (10) |
| Upper | 0 (0) | 0 (0) | 1 (4.6) | 1 (1) |
| Pouchitis postcolectomy | 1 (2.2) | 0 (0) | 0 (0) | 1 (1) |
| Perianal disease | 5 (10.9) | 6 (18.8) | 6 (27.3) | 17 (23) |
| Fistulating disease | 4 (8.7) | 13 (40.6) | 9 (40.1) | 26 (34) |
| UC or IBD-U (%) | 13 (28.3) | 8 (25) | 3 (13.6) | 24 (24) |
| Left-sided | 8 (17.4) | 6 (18.8) | 2 (9.1) | 16 (16) |
| Pancolonic | 3 (6.5) | 2 (6.2) | 1 (4.5) | 6 (6) |
| Pouchitis postcolectomy | 2 (4.4) | 0 (0) | 0 | 2 (2) |
| Active smoker, n (%) | 9 (19.6) | 6 (18.8) | 2 (9.1) | 17 (17.0) |
| Duration of disease, years, median (IQR) | 12 (7, 17) | 11 (6, 17) | 10 (6, 17) | 11 (6, 17) |
| Time since first IFX, years, median (IQR) | 4 (2, 12) | 6 (1, 14) | 5 (2, 11) | 4 (2, 12) |
| Average drug level AU/mL, median (IQR) | 3.5 (2.0, 5.1) | 2.6 (1.9, 4.1) | 2.3 (1.7, 3.4) | 2.7 (1.8, 4.5) |
IBD-U, inflammatory bowel disease unclassified; 6-TGN, 6-thioguanine; UC, ulcerative colitis.