Table 1 Characteristics of the study population
From: Factors associated with the 6-minute walk distance in patients with systemic sclerosis
| Â | N | Value | |
|---|---|---|---|
Demographic data | |||
 Females, n (%) | 298 | 242 | (81.2) |
 Age at inclusion (years), mean (SD) | 298 | 58.2 | (13.3) |
 BMI (kg/m2), mean (SD) | 283 | 24.9 | (5.3) |
 Smoking history, n (%) | 297 | 119 | (40.1) |
Diagnosis of SSc | |||
 SSc subtype | |||
  lcSSc, n (%) | 298 | 245 | (82.2) |
  dcSSc, n (%) | 298 | 53 | (17.8) |
 Disease duration at inclusion | |||
  Since diagnosis (years), mean (SD) | 298 | 9.1 | (8.1) |
  Since first non-Raynaud symptom (years), mean (SD) | 244 | 9.9 | (8.5) |
  Since Raynaud phenomenon onset (years), mean (SD) | 279 | 15.6 | (12.2) |
 Immunological profile | |||
  Anti-centromere antibodies, n (%) | 291 | 163 | (56.0) |
  Anti-topoisomerase I antibodies, n (%) | 291 | 57 | (19.6) |
  Anti-RNA polymerase III antibodies, n (%) | 291 | 7 | (2.4) |
  Anti-RNP antibodies, n (%) | 291 | 15 | (5.2) |
 Nailfold capillaroscopy | |||
  Specific organic microangiopathy, n (%) | 109 | 98 | (89.9) |
History of organ involvement | |||
 Interstitial lung disease | |||
  No ILD, n (%) | 270 | 159 | (58.9) |
  Limited ILD, n (%) | 270 | 82 | (30.4) |
  Extensive ILD, n (%) | 270 | 29 | (10.7) |
 Pulmonary arterial hypertension, n (%) | 286 | 17 | (5.9) |
 Scleroderma renal crisis, n (%) | 285 | 1 | (0.4) |
 Digital ulcers (previously or at inclusion), n (%) | 298 | 128 | (43.0) |
 Acute venous thrombosis, n (%) | 297 | 33 | (11.1) |
 Acute arterial thrombosis, n (%) | 297 | 39 | (13.1) |
 Chronic cardiovascular disease, n (%) | 296 | 21 | (7.1) |
 Clinical evaluation at inclusion | |||
 Modified Rodnan skin score, mean (SD) | 297 | 4.96 | (5.95) |
 Telangiectasia, n (%) | 275 | 199 | (72.4) |
 NYHA functional class | |||
  Class I, n (%) | 296 | 132 | (44.6) |
  Class II, n (%) | 296 | 101 | (34.1) |
  Class III, n (%) | 296 | 57 | (19.3) |
  Class IV, n (%) | 296 | 6 | (2.0) |
 Cardiovascular symptoms, n (%) | 298 | 24 | (8.1) |
 Joint symptoms, n (%) | 296 | 125 | (42.2) |
 Muscle symptoms, n (%) | 297 | 57 | (19.2) |
6-minute walk test | |||
 Total distance (m), mean (SD) | 298 | 438.3 | (108.1) |
 Total distance (% predicted), mean (SD) | 290 | 81.6 | (17.8) |
 Initial SpO2 (%), mean (SD) | 280 | 98.1 | (2.1) |
 Final SpO2 (%), mean (SD) | 275 | 97.5 | (3.3) |
 ΔSpO2 (%), mean (SD) | 276 | -0.58 | (2.72) |
 Initial Borg score, mean (SD) | 294 | 0.4 | (1.1) |
 Final Borg score, mean (SD) | 294 | 2.5 | (2.2) |
 ΔBorg score, mean (SD) | 293 | 2.1 | (1.9) |
 Initial sBP (mmHg), mean (SD) | 292 | 123.8 | (16.6) |
 Final sBP (mmHg), mean (SD) | 292 | 132.9 | (18.2) |
 ΔsBP (mmHg), mean (SD) | 291 | 9.2 | (14.0) |
 Initial dBP (mmHg), mean (SD) | 271 | 97.4 | (3.4) |
 Final dBP (mmHg), mean (SD) | 292 | 73.6 | (10.0) |
 ΔdBP (mmHg), mean (SD) | 291 | 0.95 | (10.2) |
 Initial HR (bpm), mean (SD) | 289 | 76.7 | (12.3) |
 Final HR (bpm), mean (SD) | 288 | 87.1 | (15.9) |
 ΔHR (bpm), mean (SD) | 288 | 10.4 | (11.2) |
Biological data | |||
 Hemoglobin (g/dl), mean (SD) | 291 | 13.4 | (1.4) |
 ESR (mm/h), mean (SD) | 258 | 14.8 | (15.3) |
 CRP (mg/L), mean (SD) | 293 | 4.0 | (4.7) |
 Creatinin (mg/L), mean (SD) | 294 | 8.0 | (2.8) |
 Estimated GFR (ml/min/1.73 m2), mean (SD) | 294 | 89.1 | (21.5) |
 Elevated Nt-pro-BNP, n (%) | 290 | 43 | (14.8) |
 CK (IU), mean (SD) | 289 | 93 | (59.5) |
 Ferritin (ng/ml), mean (SD) | 268 | 105.5 | (136.4) |
 Complement activation, n (%) | 265 | 9 | (3.4) |
Transthoracic echocardiography | |||
 Left ventricular ejection fraction (%), mean (SD) | 250 | 62.8 | (6.7) |
 Left ventricular diastolic dysfunction, n (%) | 229 | 124 | (54.2) |
 Valvular heart disease, n (%) | 244 | 41 | (16.8) |
 Peak TRV (m/s), mean (SD) | 98 | 2.62 | (0.54) |
 RA–RV pressure gradient (mmHg), mean (SD) | 206 | 27.4 | (13.4) |
 Estimated sPAP (mmHg), mean (SD) | 194 | 31.5 | (13.1) |
 RA area (cm2), mean (SD) | 139 | 15.0 | (4.6) |
 IVC dilation and/or decreased IVC collapse, n (%) | 210 | 16 | (7.6) |
 Pericardial effusion, n (%) | 230 | 5 | (2.2) |
Pulmonary function tests | |||
 TLC (% predicted), mean (SD) | 276 | 96.2 | (16.4) |
 FVC (% predicted), mean (SD) | 287 | 103.5 | (21.8) |
 FEV1 (% predicted), mean (SD) | 286 | 95.1 | (21.8) |
 FEV1/FVC (%), mean (SD) | 286 | 79.2 | (10.7) |
 DLCO (% predicted), mean (SD) | 285 | 70.0 | (19.7) |
 KCO (% predicted), mean (SD) | 278 | 80.9 | (17.6) |
Composite scores | |||
 EScSG-AI score, mean (SD) | 289 | 1.16 | (1.2) |
 Medsger severity score, mean (SD) | 228 | 4.17 | (2.5) |
 HAQ-DI score, mean (SD) | 223 | 0.61 | (0.7) |
Treatments | |||
 Negative chronotropic drugs, n (%) | 293 | 87 | (29.7) |
 Positive chronotropic drugs, n (%) | 293 | 10 | (3.4) |