Patients’ demographic and clinical characteristics at baseline in the derivation cohort
| Characteristics | Derivation cohort (n=98) | Progressors (n=25) | Non-progressors (n=73) | P values |
| Demographic | ||||
| Age (year) | 57.3±12.9 | 61.6±12.7 | 55.9±12.8 | 0.058 |
| Male sex | 20 (20.4) | 7 (28.0) | 13 (17.8) | 0.275 |
| Disease duration (year)* | 6.1±5.6 | 6.1±6.6 | 6.1±5.3 | 0.702 |
| Smoker ever | 30 (30.6) | 10 (40.0) | 20 (27.4) | 0.238 |
| Extrapulmonary | ||||
| Anti-Scl-70 positive | 39 (39.8) | 10 (40.0) | 29 (39.7) | 0.981 |
| ACA positive | 24 (24.5) | 4 (16.0) | 20 (27.4) | 0.253 |
| Anti-CCP positive | 3/86 (3.5) | 1/23 (4.3) | 2/63 (3.2) | 1.000 |
| Diffuse cutaneous subset | 30 (30.6) | 10 (40.0) | 20 (27.4) | 0.238 |
| mRSS (unit) | 7.6±8.3 | 10.1±8.9 | 6.8±8.0 | 0.046 |
| Digital ulcers ever | 46 (46.9) | 15 (60.0) | 31 (42.5) | 0.129 |
| Arthritis ever† | 27 (27.6) | 15 (60.0) | 12 (16.4) | <0.001 |
| Joint contractures | 40 (40.8) | 15 (60.0) | 25 (34.2) | 0.024 |
| ESR>20 mm/1 hour | 33/97 (34.0) | 11 (44.0) | 22/72 (30.6) | 0.222 |
| CRP elevation | 25 (25.5) | 7 (28.0) | 18 (24.7) | 0.741 |
| Lung-associated | ||||
| FVC (% predicted) | 101.9±17.6 | 102.9±16.7 | 101.5±18.0 | 0.736 |
| DLCO (% predicted) | 76.5±17.1 | 73.2±15.0 | 77.6±17.7 | 0.268 |
| Ground glass opacification | 40 (40.8) | 9 (36.0) | 31 (42.5) | 0.570 |
| Honey combing | 3 (3.1) | 1 (4.0) | 2 (2.7) | 1.000 |
| Dyspnoea NYHA≥2 | 42 (42.9) | 15 (60.0) | 27 (37.0) | 0.045 |
| 6 min walk distance (m) | 524.0±99.3 | 483.6±105.6 | 537.8±93.8 | 0.037 |
| SpO2 before 6MWT (%) | 96.8±1.6 | 96.0±2.2 | 97.1±1.2 | 0.022 |
| SpO2 after 6MWT (%) | 94.7±3.4 (n=97) | 92.4±3.8 | 95.5±2.8 (n=72) | <0.001 |
| Oxygen desaturation (%) | 2.1±2.9 (n=97) | 3.6±3.2 | 1.6±2.6 (n=72) | 0.002 |
| Active disease (VAI>3)‡33 | 15 (15.3) | 5 (20.0) | 10 (13.7) | 0.522 |
| Immunosuppressive therapy§ | 41 (41.8) | 16 (64.0) | 25 (34.2) | 0.009 |
Data are presented as mean±SD for continuous variables and number (frequency) (%) for categorical variables.
*Disease duration was calculated as difference between the date of the baseline visit and the date of the first non-Raynaud’s symptom of the disease as reported by the patients.
†Arthritis ever was defined as one or more tender and swollen joints as judged by the treating physician ever existed currently or before the baseline visit.
‡Active disease was defined as scored >3 by calculating European Scleroderma Study Group (EScSG) disease activity indices for SSc proposed by Valentini et al.33
§Immunosuppressive therapy was defined as treatment with prednisone in doses >10 mg/day or any immunosuppressant (cyclophosphamide, methotrexate, azathioprine, mycophenolate, rituximab and tocilizumab) at baseline.
6MWT, 6 min walk test; ACA, anticentromere antibody; anti-CCP, anticyclic citrullinated peptide; anti-Scl-70, antitopoisomerase-I antibodies; CRP, C reactive protein; DLCO, diffusing capacity for carbon monoxide; ESR, erythrocyte sedimentation rate; FVC, forced vital capacity; mRSS, modified Rodnan Skin Score; NYHA, New York Heart Association; SpO2, peripheral capillary oxygen saturation; VAI, Valentini Activity Index.