Clinical features of the study patients according to timing of antibiotic administration
| Feature | Before ICI therapy (n = 186) | After ICI therapy and before IMDC onset (n = 84) | Both (n = 299) | p |
|---|---|---|---|---|
| Indication for antibiotic, n (%) | 0.015 | |||
| Upper respiratory infection | 4 (2.2) | 3 (3.6) | 14 (4.7) | |
| Lower respiratory infection | 16 (8.6) | 3 (3.6) | 19 (6.4) | |
| Gastrointestinal infection | 12 (6.5) | 20 (23.8) | 36 (12.0) | |
| Urinary tract infection | 19 (10.2) | 8 (9.5) | 35 (11.7) | |
| Skin/Soft tissue infection | 13 (7.0) | 9 (10.7) | 21 (7.0) | |
| Sepsis and bacteremia | 5 (2.7) | 3 (3.6) | 3 (1.0) | |
| Fever of unknown origin/empirical coverage | 52 (28.0) | 20 (23.8) | 94 (31.4) | |
| Prophylaxis | 35 (18.8) | 9 (10.7) | 46 (15.4) | |
| Multiple infections | 21 (11.3) | 9 (10.7) | 24 (8.0) | |
| Not recorded | 9 (4.8) | 0 (0.0) | 7 (2.3) | |
| IMDC, n (%) | 56 (30.1) | 84 (100.0) | 127 (42.5) | < 0.001 |
| Immunosuppressive therapy for IMDC, n (%) | 33 (17.7) | 65 (77.4) | 75 (25.1) | < 0.001 |
| Median time to IMDC onset, weeks (IQR) | 11 (8–16) | 9 (5–14) | 5 (2–11) | 0.134 |
| Median duration of IMDC symptoms, days (IQR) | 10 (4–21) | 10 (4–20) | 10 (4–19) | 0.801 |
| Hospitalization, n (%) | 33 (58.9) | 62 (73.8) | 73 (57.5) | 0.044 |
| Median duration of hospitalization, days (IQR) | 5 (3–8) | 7 (3–12) | 6 (3–9) | 0.234 |
| ICU admission, n (%) | 1 (1.8) | 3 (3.6) | 6 (4.7) | 0.625 |
| Grade of colitis, n (%) | 0.413 | |||
| 1 | 12 (30.0) | 9 (12.5) | 21 (23.1) | |
| 2 | 17 (42.5) | 35 (48.6) | 38 (41.8) | |
| 3 | 10 (25.0) | 25 (34.7) | 30 (33.0) | |
| 4 | 1 (2.5) | 3 (4.2) | 2 (2.2) | |
| Grade of diarrhea, n (%) | 0.976 | |||
| 1 | 17 (30.4) | 21 (25.0) | 39 (30.7) | |
| 2 | 14 (25.0) | 24 (28.6) | 31 (24.4) | |
| 3 | 22 (39.3) | 33 (39.3) | 48 (37.8) | |
| 4 | 3 (5.4) | 6 (7.1) | 9 (7.1) | |
| Intravenous steroid administration, n (%) | 14 (46.7) | 41 (65.1) | 44 (61.1) | 0.232 |
| Infliximab/vedolizumab administration, n (%) | 6 (10.7) | 22 (26.2) | 24 (18.9) | 0.075 |
| Recurrence of IMDC, n (%) | 8 (14.3) | 16 (19.0) | 18 (14.2) | 0.601 |
| Colon perforation, n (%) | 1 (1.8) | 1 (1.2) | 2 (1.6) | 1.000 |