Table 1.
Baseline demographic and clinical characteristics of skin progressors and non-progressors
| Characteristics | Missing cases, n (%) | Whole cohort (n=1021) | Progressors (n=78) | Non-progressors (n=943) | P value |
| Demographic | |||||
| Age, years (mean±SD) | 0 (0) | 52.0±13.7 | 51.7±12.9 | 52.0±13.7 | 0.869 |
| Male sex | 0 (0) | 248 (24.3) | 30 (38.5) | 218 (23.1) | 0.004 |
| Disease duration* years (mean±SD) | 78 (7.6) | 7.7±7.5 | 5.3±6.2 | 7.9±7.5 | 0.006 |
| ≤15 months | 78 (7.6) | 126 (13.4) | 19 (27.9) | 107 (12.2) | <0.001 |
| ≤36 months | 78 (7.6) | 298 (31.6) | 36 (52.9) | 262 (29.9) | <0.001 |
| Vascular | |||||
| Raynaud’s phenomenon | 2 (0.2) | 997 (97.8) | 74 (94.9) | 923 (98.1) | 0.141 |
| Digital ulcers | 11 (1.1) | 384 (38.0) | 30 (38.5) | 354 (38.0) | 1.000 |
| Active digital ulcers | 25 (2.4) | 199 (20.0) | 16 (21.1) | 183 (19.9) | 0.925 |
| Skin | |||||
| mRSS, unit (mean±SD) | 0 (0) | 16.9±7.7 | 14.8±6.2 | 17.1±7.7 | 0.010 |
| mRSS ≤22/51 | 0 (0) | 819 (80.2) | 67 (85.9) | 752 (79.7) | 0.245 |
| Musculoskeletal | |||||
| Tendon friction rubs | 11 (1.1) | 156 (15.4) | 10 (13.0) | 146 (15.6) | 0.648 |
| Joint synovitis | 6 (0.6) | 180 (17.7) | 16 (20.5) | 164 (17.5) | 0.607 |
| Joint contractures | 7 (0.7) | 505 (49.8) | 42 (53.8) | 463 (49.5) | 0.532 |
| Muscle weakness | 6 (0.6) | 255 (25.1) | 17 (22.1) | 238 (25.4) | 0.614 |
| Gastrointestinal | |||||
| Oesophageal symptoms | 1 (0.1) | 687 (67.4) | 51 (65.4) | 636 (67.5) | 0.795 |
| Stomach symptoms | 2 (0.2) | 300 (29.4) | 27 (34.6) | 273 (29.0) | 0.361 |
| Intestinal symptoms | 3 (0.3) | 281 (27.6) | 21 (26.9) | 260 (27.7) | 0.994 |
| Cardiopulmonary | |||||
| Dyspnoea (NYHA) | 84 (8.2) | 0.186 | |||
| Stage 1 | 520 (55.5) | 34 (51.5) | 486 (55.8) | ||
| Stage 2 | 315 (33.6) | 28 (42.4) | 287 (33.0) | ||
| Stage 3/4 | 102 (10.9) | 4 (6.1) | 98 (11.2) | ||
| Diastolic dysfunction | 150 (14.7) | 195 (22.4) | 12 (18.5) | 183 (22.7) | 0.526 |
| Pericardial effusion | 215 (21.1) | 59 (7.3) | 7 (12.1) | 52 (7.0) | 0.238 |
| Conduction blocks | 124 (12.1) | 123 (13.7) | 6 (8.8) | 117 (14.1) | 0.300 |
| LVEF <45% | 266 (26.1) | 16 (2.1) | 2 (3.4) | 14 (2.0) | 0.797 |
| Pulmonary hypertension byechocardiography† | 138 (13.5) | 120 (13.6) | 11 (16.7) | 109 (13.3) | 0.568 |
| Lung fibrosis on CT scan | 351 (34.4) | 403 (60.1) | 33 (60.0) | 370 (60.2) | 1.000 |
| FVC, % predicted (mean±SD) | 168 (16.5) | 87.0±20.7 | 86.6±17.5 | 87.0±20.9 | 0.879 |
| FVC <70% predicted | 168 (16.5) | 182 (21.3) | 13 (21.7) | 169 (21.3) | 1.000 |
| FEV1, % predicted (mean±SD) | 272 (26.6) | 85.7±18.4 | 87.2±16.5 | 85.6±18.6 | 0.547 |
| TLC, % predicted (mean±SD) | 427 (41.8) | 86.6±20.6 | 86.5±15.3 | 86.6±20.9 | 0.991 |
| DLCO, % predicted (mean±SD) | 179 (17.5) | 65.6±19.3 | 65.6±17.2 | 65.6±19.4 | 0.995 |
| DLCO <70% predicted | 179 (17.5) | 479 (56.9) | 33 (57.9) | 446 (56.8) | 0.984 |
| Kidney | |||||
| Renal crisis history | 4 (0.4) | 30 (2.9) | 2 (2.6) | 28 (3.0) | 1.000 |
| Laboratory parameters | |||||
| ANA positive | 16 (1.6) | 961 (95.6) | 75 (96.2) | 886 (95.6) | 1.000 |
| ACA positive | 64 (6.3) | 88 (9.2) | 6 (8.2) | 82 (9.3) | 0.929 |
| Anti-Scl-70 positive | 42 (4.1) | 616 (62.9) | 49 (66.2) | 567 (62.7) | 0.628 |
| Anti-U1RNP positive | 237 (23.2) | 35 (4.5) | 1 (1.6) | 34 (4.7) | 0.514 |
| Anti-RNA polymerase III positive | 453 (44.4) | 58 (10.2) | 5 (9.8) | 53 (10.3) | 1.000 |
| Creatinine kinase elevation | 75 (7.3) | 100 (10.6) | 8 (10.8) | 92 (10.6) | 1.000 |
| Proteinuria | 78 (7.6) | 64 (6.8) | 5 (6.9) | 59 (6.8) | 1.000 |
| Hypocomplementaemia | 192 (18.8) | 58 (7.0) | 3 (4.8) | 55 (7.2) | 0.613 |
| ESR >25 mm/h | 117 (11.5) | 371 (41.0) | 24 (35.3) | 347 (41.5) | 0.382 |
| CRP elevation | 63 (6.2) | 294 (30.7) | 31 (41.9) | 263 (29.8) | 0.041 |
| Active disease (VAI >3)‡ | 154 (15.1) | 340 (39.2) | 20 (30.8) | 320 (39.9) | 0.187 |
| Immunosuppressive therapy§ | 66 (6.5) | 667 (69.8) | 54 (73.0) | 613 (69.6) | 0.632 |
Definitions of items and organ manifestation are according to EUSTAR.14
Data are presented as number (%) unless otherwise stated.
P values of univariate comparisons of baseline characteristics between skin progressors and non-progressors are shown (χ2 tests or Fisher’s exact tests used for categorical variables and independent sample t-tests used for continuous variables, as appropriate).
*Disease duration was calculated as the 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 patient.
†Pulmonary hypertension was globally judged on echocardiography by the treating physician.
‡Active disease was defined as a score >3 by calculating European Scleroderma Study Group disease activity indices for systemic sclerosis proposed by Valentini et al.45
§Immunosuppressive therapy was defined as treatment with corticosteroids (prednisone dose ≥2.5 mg/day or other dosage forms in equal dose) or any immunosuppressant.
ACA, anti-centromere antibody;ANA, antinuclear antibody;Anti-Scl-70, anti-topoisomerase 1 antibody;CRP, C reactive protein;CT, computed tomography; DLCO, diffusing capacity for carbon monoxide;ESR, erythrocyte sedimentation rate; FEV1, forced expiratory volume in 1 sec; FVC, forced vital capacity; LVEF, left ventricular ejection fraction; mRSS, modified Rodnan skin score. NYHA, New York Heart Association;TLC, total lung capacity;VAI, Valentini activity index;