Characteristics of the derivation sample and the validation sample*
| Item | Derivation sample | p Value | Validation sample | p Value | ||
|---|---|---|---|---|---|---|
| SSc (n=100) | Scleroderma-like disorder (n=100) | SSc (n=268) | Scleroderma-like disorder (n=137) | |||
| Age, mean±SD years | 55±13 | 51±15 | 0.05 | 54±13 | 52±15 | 0.17 |
| Female | 86 (86) | 79 (79) | 0.25 | 221 (83) | 101 (75) | 0.08 |
| Region | ||||||
| North America | 50 | 50 | – | 191 (68) | 91 (32) | 0.32 |
| Europe | 50 | 50 | 77 (63) | 46 (37) | ||
| Time since onset of Raynaud's phenomenon, median (IQR) years | 13 (7–18) | 12 (4–18) | 0.42 | 9 (5–18) | 10 (4–22) | 0.40 |
| Time since first non-Raynaud's symptom, median (IQR) years | 10 (4–13) | 9 (2–14) | 0.58 | 7 (3–12) | 7 (3–15) | 0.89 |
| Time since diagnosis, median (IQR) years | 8 (3–12) | 6 (1–9) | 0.10 | 5 (2–11) | 4 (1–7) | 0.016 |
| Scleroderma-like disorders | ||||||
| Systemic lupus erythematosus | – | 28 (28) | – | – | 32 (23) | – |
| Polymyositis/dermatomyositis | – | 23 (23) | – | – | 21 (15) | – |
| Primary Raynaud's phenomenon | – | 19 (19) | – | – | 7 (5) | – |
| Mixed connective tissue disease | – | 9 (9) | – | – | 14 (10) | – |
| Undifferentiated connective tissue disease | – | 8 (8) | – | – | 17 (12) | – |
| Eosinophilic fasciitis | – | 6 (6) | – | – | 16 (12) | – |
| Nephrogenic sclerosing fibrosis | – | 3 (3) | – | – | 3 (2) | – |
| Generalised morphea | – | 5 (5) | – | – | 8 (6) | – |
| Scleromyxedema | – | 1 (1) | – | – | 3 (2) | – |
| Graft-versus-host disease | – | 3 (3) | – | – | 3 (2) | – |
| Other diagnoses | – | 8 (8) | – | – | 13 (9) | – |
| Manifestations† | ||||||
| Raynaud's phenomenon | 91 (91) | 49 (49) | <0.0001 | 257 (96) | 63 (46) | <0.0001 |
| Autoantibodies | 68 (68) | 7 (7) | <0.0001 | 137 (51) | 15 (11) | <0.0001 |
| Anticentromere antibody | 33 (33) | 5 (5) | <0.0001 | 41 (15) | 8 (6) | 0.0057 |
| Anti–topoisomerase-I | 34 (34) | 1 (1) | <0.0001 | 69 (26) | 7 (5) | <0.0001 |
| Anti–RNA polymerase III | 2 (2) | 1 (1) | 1.0 | 27 (10) | 0 | <0.0001 |
| Puffy fingers | 61 (61) | 17 (17) | <0.0001 | 169 (63) | 24 (18) | <0.0001 |
| Abnormal nailfold capillaries | 54 (54) | 24 (24) | <0.0001 | 146 (54) | 51 (37) | 0.0010 |
| Dilated vessels | 37 (37) | 28 (28) | 0.08 | 124 (46) | 34 (25) | 0.0080 |
| Avascular areas | 21 (21) | 11 (11) | 0.08 | 86 (32) | 9 (7) | <0.0001 |
| Haemorrhages | 12 (12) | 9 (9) | 0.64 | 63 (24) | 8 (6) | <0.0001 |
| Digital tip ulcers | 53 (53) | 8 (8) | <0.0001 | 108 (40) | 12 (9) | <0.0001 |
| Pitting scars | 53 (53) | 5 (5) | <0.0001 | 105 (39) | 5 (4) | <0.0001 |
| PAH or ILD | 48 (48) | 14 (14) | <0.0001 | 138 (52) | 14 (10) | <0.0001 |
| PAH | 44 (44) | 10 (10) | <0.0001 | 20 (7) | 2 (1) | 0.012 |
| ILD | 12 (12) | 4 (4) | 0.037 | 131 (49) | 12 (9) | <0.0001 |
| Telangiectasia | 35 (35) | 10 (10) | <0.0001 | 68 (25) | 13 (9) | 0.0002 |
| Skin thickening of fingers to proximal of MCP joints | 26 (26) | 1 (1) | <0.0001 | 105 (39) | 6 (4) | <0.0001 |
| Skin thickening of fingers distal to MCP joints | 5 (5) | 38 (38) | <0.0001 | 178 (66) | 24 (18) | <0.0001 |
*Data were prospectively collected on 605 consecutive patients with systemic sclerosis (SSc) or a scleroderma-like disorder (see Methods); half of the SSc patients at each site were to have early SSc. A random sample of 100 SSc cases and 100 controls, 50% from North America and 50% from Europe, was selected to form the derivation sample, and the remaining patients formed the validation sample. Except where indicated otherwise, values are the number (%).
†Listed in order of frequency of occurrence in the SSc derivation sample.
ILD, interstitial lung disease; MCP, metacarpophalangeal; PAH, pulmonary arterial hypertension.