| Whole cohort (n = 164) | ISG negative (n = 101) | ISG positive (n = 63) | p value (ISG positive vs. negative) |
---|---|---|---|---|
Age (years) | 48.5 (36.8, 57.3) | 50.3 (40.6, 59.5) | 44.8 (31.6, 52.8) | 0.012 |
Gender, female | 155 (94.5) | 97 (96.0) | 58 (92.1) | 0.277 |
Disease duration (years) n = 158 | 7.11 (3.16, 15.8) | 6.84 (3.06, 15.3) | 8.08 (3.56, 16.1) | 0.538 |
Age at disease onset (years) | 36.5 (26.2, 47.4) | 40.5 (30.1, 48.4) | 31.6 (23.6, 41.1) | 0.005 |
Ethnicity | ||||
 Caucasian | 122 (74.8) | 80 (79.2) | 42 (66.7) | 0.430 |
 Mixed | 1 (0.6) | 1 (0.99) | 0 | |
 Asian or Asian British | 8 (4.9) | 3 (2.97) | 5 (7.94) | |
 Black or Black British | 24 (14.6) | 12 (11.9) | 12 (19.0) | |
 Other | 10 (6.1) | 4 (3.96) | 4 (6.35) | |
 Unknown | 1 | 1 (0.99) | 0 | |
Disease group | ||||
 UCTD | 43 (26.2) | 34 (33.7) | 9 (14.3) | < 0.0001 |
 SLE | 67 (40.9) | 40 (39.6) | 27 (42.9) | |
 MCTD | 13 (7.93) | 4 (3.96) | 9 (14.3) | |
 SS | 20 (12.2) | 6 (5.94) | 14 (22.2) | |
 IIM | 8 (4.88) | 6 (5.94) | 2 (3.17) | |
 SSc | 13 (7.93) | 11 (10.9) | 2 (3.17) | |
Concomitant medication use | ||||
 Oral prednisolone | 45 (27.3) | 28 (27.7) | 17 (27.0) | 0.918 |
 Anti-malarial* | 96 (58.5) | 64 (63.4) | 32 (50.8) | 0.112 |
 Immunosuppressant** | 47 (28.7) | 28 (27.7) | 19 (30.2) | 0.737 |
 Biological agent (within 6 months) | 2 (1.22) | 2 (1.98) | 0 | 0.261 |
 Daily dose prednisolone (mg) | 7.5 (5.0, 10) | 7.5 (5.0, 10) | 7.5 (6.25, 10) | 0.552 |
Autoantibodies | ||||
 dsDNA | 46 (28.0) | 24 (23.8) | 22 (34.9) | 0.122 |
 Ro/SS-A | 49 (29.9) | 18 (17.8) | 31 (49.2) | < 0.0001 |
 La/SS-B | 23 (14.0) | 9 (8.91) | 14 (22.2) | 0.017 |
 Smith | 23 (14.0) | 5 (4.95) | 18 (28.6) | < 0.0001 |
 RNP | 39 (23.8) | 13 (12.9) | 26 (41.3) | < 0.0001 |
 Chromatin | 33 (20.1) | 9 (8.91) | 24 (38.1) | < 0.0001 |
 Rheumatoid factor | 37 (22.6) | 12 (11.9) | 25 (29.7) | < 0.0001 |
 CCP | 7 (4.3) | 3 (2.97) | 4 (6.35) | 0.298 |
 SSC-specific†| 15 (9.1) | 11 (10.9) | 4 (6.35) | 0.326 |
 Jo-1 | 4 (2.4) | 3 (2.97) | 1 (1.59) | 0.577 |
Clinical features | ||||
 Photosensitivity | 64 (39.3) | 43 (42.6) | 21/62 (33.9) | 0.174 |
 Myositis-specific rash | 10 (6.10) | 7 (6.93) | 3 (4.76) | 0.419 |
 Discoid lesion | 6 (3.68) | 3 (2.97) | 3/62 (4.84) | 0.414 |
 Mucosal ulcers | 63 (38.7) | 41 (40.6) | 22/62 (35.5) | 0.315 |
 Raynaud’s syndrome | 87 (53.4) | 55 (54.5) | 32/62 (51.6) | 0.424 |
 Inflammatory arthritis | 75 (46.0) | 42/100 (42.0) | 33 (52.4) | 0.129 |
 Renal disease‡ | 24 (14.9) | 13/99 (13.1) | 11/62 (17.7) | 0.281 |
 Neurological disease ‡ | 4 (2.44) | 2 (1.98) | 2 (3.17) | 0.498 |
 Haematological disorder‡ | 74 (46.3) | 35/99 (35.4) | 39/61 (63.9) | < 0.0001 |