Table 2.
Baseline characteristics of cohort 2 (RKD)
| Characteristics | Total | GPA | MPA | EGPA | p |
|---|---|---|---|---|---|
| n (%) | 439 | 196 (44.6) | 220 (50.1) | 23 (5.2) | |
| Age (years, median [IQR]) | 59.0 [48.0, 69.0] | 54.0 [40.0, 62.3] | 65.0 [54.0, 73.0] | 57.0 [51.5, 62.5] | < 0.001 |
| Male (%) | 253 (57.6) | 112 (57.1) | 129 (58.6) | 12 (52.2) | 0.823 |
| Ethnicity (%) | 0.353 | ||||
| White | 433 (98.6) | 194 (99.0) | 217 (98.6) | 22 (95.7) | |
| Asian | 6 (1.4) | 2 (1.0) | 3 (1.4) | 1 (4.3) | |
| ANCA subtype (ELISA) (%) | < 0.001 | ||||
| PR3 | 219 (49.9) | 170 (86.7) | 45 (20.5) | 4 (17.4) | |
| MPO | 207 (47.2) | 19 (9.7) | 172 (78.2) | 16 (69.6) | |
| ELISA-negative | 12 (2.7) | 6 (3.1) | 3 (1.4) | 3 (13.0) | |
| No ELISA recorded | 1 (0.2) | 1 (0.5) | 0 (0.0) | 0 (0.0) | |
| Organ involvement (%) | |||||
| Musculoskeletal | 168 (38.3) | 103 (52.6) | 53 (24.1) | 12 (52.2) | < 0.001 |
| Mucocutaneous | 115 (26.2) | 71 (36.2) | 34 (15.5) | 10 (43.5) | < 0.001 |
| Eyes | 57 (13.0) | 37 (18.9) | 18 (8.2) | 2 (8.7) | 0.004 |
| Lung | 229 (52.2) | 132 (67.3) | 78 (35.5) | 19 (82.6) | < 0.001 |
| Neurological | 60 (13.7) | 27 (13.8) | 22 (10.0) | 11 (47.8) | < 0.001 |
| Ears, nose, throat | 193 (44.0) | 147 (75.0) | 29 (13.2) | 17 (73.9) | < 0.001 |
| Cardiovascular | 12 (2.7) | 6 (3.1) | 6 (2.7) | 0 (0.0) | 1 |
| Kidney | 370 (84.3) | 146 (74.5) | 212 (96.4) | 12 (52.2) | < 0.001 |
| Gastrointestinal | 25 (5.7) | 13 (6.6) | 11 (5.0) | 1 (4.3) | 0.828 |
| Latitude (degrees, median [IQR]) | 53.30 [52.67, 53.39] | 53.29 [52.67, 53.39] | 53.32 [52.76, 53.39] | 53.29 [52.86, 53.37] | 0.350 |
| Longitude (degrees, median [IQR]) | − 6.39 [− 7.77, − 6.30] | − 6.43 [− 8.37, − 6.27] | − 6.48 [− 8.35, − 6.22] | − 6.39 [− 7.77, − 6.30] | 0.684 |
| CW-D-UVB at symptom onset (kJ/m2, median [IQR]) | 75.98 [19.12, 161.06] | 78.46 [20.29, 166.07] | 74.57 [18.94, 153.51] | 60.41 [30.27, 115.27] | 0.842 |
| Season of diagnosis (%) | 0.502 | ||||
| Spring | 129 (29.4) | 60 (30.6) | 67 (30.5) | 2 (8.7) | |
| Summer | 92 (21.0) | 41 (20.9) | 44 (20.0) | 7 (30.4) | |
| Autumn | 112 (25.5) | 48 (24.5) | 57 (25.9) | 7 (30.4) | |
| Winter | 106 (24.1) | 47 (24.0) | 52 (23.6) | 7 (30.4) | |
| Follow-up (months, median [IQR]) | 58.3 [32.1, 138.1] | 84.7 [39.5, 183.9] | 45.4 [26.0, 83.8] | 108.4 [49.8, 160.2] | < 0.001 |
| Death (%) | 38 (8.7) | 11 (5.6) | 25 (11.4) | 2 (8.7) | 0.112 |
| Number of patients experiencing n relapse(s) (%) | |||||
| 0 | 343 (78.1) | 141 (71.9) | 188 (85.5) | 14 (60.9) | |
| 1 | 67 (15.3) | 37 (18.9) | 26 (11.8) | 4 (17.4) | |
| 2 | 20 (4.6) | 12 (6.1) | 4 (1.8) | 4 (17.4) | |
| 3 | 8 (1.8) | 5 (2.6) | 2 (0.9) | 1 (4.3) | |
| 4 | 1 (0.2) | 1 (0.5) | 0 (0) | 0 (0) | |
Refer to supplementary materials for the definitions of ‘date of symptom onset’ and seasons. Refer to Additional file 1: Table S1 for the details on the induction and maintenance treatment. Continuous variables are reported as mean (standard deviation (SD)) or median (interquartile range (IQR)) if not normally distributed and compared using the independent sample t-test or the Mann-Whitney U test, respectively. Categorical variables are summarised by frequency and percentage (%) and compared using the χ2 test
ANCA anti-neutrophil cytoplasmic antibodies, ELISA enzyme-linked immunoassay, PR3 proteinase-3, MPO myeloperoxidase, CW-DUVB cumulative-weighted UVB dose, SD standard deviation, IQR inter-quartile range