Baseline characteristics before and after multiple imputation and propensity score matching
| TCZ-treated patients | Patients without TCZ, potential controls | ||||
| Before MICE and PSM | Randomly drawn data set after MICE and PSM | ||||
| N=93 | N=3180 | SMD | N=93 | SMD | |
| Age (mean±SD; years) | 50.9±13.5 | 56.8±13.7 | 0.43 | 48.4±15.1 | 0.18 |
| Sex | |||||
| Female (n, %) | 73 (78.5) | 2637 (82.9) | 0.11 | 73 (78.5) | <0.001 |
| Systemic sclerosis subtype | |||||
| Diffuse (n, %) | 49 (57.6.) | 1319 (41.6) | 0.33 | 52 (55.9) | 0.02 |
| Immunosuppressive co-therapy | |||||
| Yes | 70 (80.5) | 882 (29.4) | 1.20 | 75 (80.6) | <0.001 |
| Prednisone ≥10 mg/day (n, %) | 41 (48.8) | 214 (7.5) | 1.04 | 16 (17.2) | 0.68 |
| Cyclophosphamide (n, %) | – | 146 (5.0) | – | 6 (7.2) | – |
| Methotrexate (n, %) | 36 (50.0) | 336 (11.3) | 0.92 | 31 (33.3) | 0.22 |
| Azathioprine (n, %) | 6 (9.2) | 198 (6.7) | 0.09 | 20 (21.5) | 0.45 |
| Mycophenolate mofetil (n, %) | 4 (6.7) | 232 (7.8) | 0.05 | 18 (19.4) | 0.39 |
| D-Penicillamine (n, %) | – | 21 (0.7) | – | 0 (0.0) | – |
| Rituximab within 6 months (n, %) | 1 (1.1) | 42 (1.3) | 0.02 | 1 (1.1) | <0.001 |
| Imatinib (n, %) | 0 (0.0) | 1 (0.0) | – | 0 (0.0) | – |
| TNF-alpha antagonist (n, %) | 0 (0.0) | 10 (0.3) | 0.08 | 0 (0.0) | <0.001 |
| Abatacept (n, %) | 1 (1.1) | – | – | 1 (1.1) | – |
| Disease duration (mean±SD, years) | 6.4±5.4 | 10.6±7.5 | 0.65 | 6.2±4.9 | 0.04 |
| Autoantibodies positive | |||||
| ANA (n, %) | 73 (92.4) | 2789 (95.7) | 0.14 | 78 (96.3) | 0.17 |
| ACA (n, %) | 12 (16.7) | 1054 (38.0) | 0.49 | 10 (13.5) | 0.09 |
| Anti-Scl-70 (n, %) | 54 (65.1) | 1013 (36.3) | 0.60 | 42 (53.8) | 0.23 |
| CRP ≥5 mg/L (n, %) | 49 (56.3) | 250 (8.0) | 1.21 | 11 (12.1) | 1.054 |
| ESR >25 mm/h (n, %) | 38 (54.3) | 867 (30.4) | 0.50 | 29 (34.9) | 0.40 |
| Baseline mRSS (median, IQR) | 14.0 (6.0, 22.2) | 6.0 (2.0, 11.0) | 0.79 | 11.0 (6.0, 21.0) | 0.07 |
| Baseline FVC % predicted (mean±SD) | 84.9±19.6 | 95.8±21.6 | 0.52 | 88.0±22.8 | 0.01 |
| Baseline DLCO % predicted (mean±SD) | 62.2±22.4 | 67.5±19.9 | 0.25 | 65.1 (19.0) | 0.12 |
| HRCT or X-ray positive for ILD (n, %) | 49 (73.1) | 1276 (48.3) | 0.53 | 37 (47.4) | 0.54 |
| Digital ulcers (n, %) | 16 (17.8) | 274 (12.2) | 0.16 | 12 (18.5) | 0.02 |
| Joint synovitis (n, %) | 44 (62.0) | 320 (10.2) | 1.28 | 14 (15.4) | 1.09 |
| Tendon friction rubs (n, %) | 25 (31.2) | 184 (6.0) | 0.69 | 11 (12.1) | 0.48 |
Demographics and clinical characteristics are defined according to EUSTAR criteria.39 The standardised mean difference (SMD) is a measure for assessing balance of distributions, values <0.1 indicate balanced covariates between matched samples.
ACA, anti-centromere antibodies; ANA, antinuclear antibodies; anti-Scl-70, anti-topoisomerase antibodies; CRP, C reactive protein; DLCO, diffusing capacity for carbon monoxide; ESR, erythrocyte sedimentation rate; FVC, forced vital capacity; ILD, interstitial lung disease; MICE, multiple imputation using chained equations; mRSS, modified Rodnan skin score; PSM, propensity score matching; RNA-pol III, anti-polymerase III; TCZ, tocilizumab.