Demographic characteristics of the derivation and validation cohorts
| Derivation cohort | Validation cohort | |||
| SLE | Non-SLE | SLE | Non-SLE | |
| n | 501 | 500 | 696 | 574 |
| Female/male | 447/54 | 421/79 | 608/88 | 490/84 |
| Age (mean±SD) years | 45±14 | 54±16 | 45±14 | 56±16 |
| Disease duration (mean±SD) years | 11±8 | 9±8 | 11±8 | 9±8 |
| Ethnicity | ||||
| Black | 29 | 10 | 56 | 12 |
| East Asian | 36 | 29 | 53 | 34 |
| Hispanic | 59 | 48 | 73 | 51 |
| South/South East Asian | 16 | 6 | 21 | 11 |
| White | 355 | 404 | 480 | 461 |
| Other | 6 | 3 | 13 | 5 |
| SLE | 501 | 696 | ||
| Non-SLE | 500 | 574 | ||
| Adult onset still’s disease | 2 | 11 | ||
| Autoimmune thyroiditis | 6 | 5 | ||
| Behcet’s disease | 7 | 9 | ||
| Cancer | 2 | 3 | ||
| Inflammatory myositis | 37 | 27 | ||
| Fibromyalgia | 6 | 3 | ||
| Membranous nephritis | 11 | 14 | ||
| Mixed connective tissue disease | 9 | 15 | ||
| Osteoarthritis | 2 | NA | ||
| Primary antiphospholipid antibody syndrome | 45 | 48 | ||
| Psoriatic arthritis | 12 | 9 | ||
| Rheumatoid arthritis | 94 | 110 | ||
| Sarcoidosis | 2 | 2 | ||
| Sjögren’s syndrome | 112 | 124 | ||
| Spondyloarthritis | 5 | 5 | ||
| Systemic sclerosis | 99 | 120 | ||
| Tuberculosis | 0 | 2 | ||
| Undifferentiated connective tissue disease | 16 | 20 | ||
| Vasculitis | 9 | 13 | ||
| Viral infection | 5 | 5 | ||
| Other | 19 | 29 | ||
Inflammatory myositis includes dermatomyositis, polymyositis and juvenile dermatomyositis
SLE, systemic lupus erythematosus.