Table 1

Characteristics of progressors and non-progressors according to clinical features and autoantibody status (at baseline)

CharacteristicsProgressor, n=66 (22.5%)Non-progressor, n=227 (77.5%)PTotal, n=293 (100%)Missing at baseline, n (%)
mRSS (0–51)19 (16–23)21 (16–27)0.03021 (16–26)0 (0)
Months since onset of skin thickening8.1 (4.7–16.0)12.6 (8.1–22.0)0.00112.0 (7.0–21.0)14 (4.8)
Pulmonary fibrosis, n (%)9 (13.6)31 (13.7)140 (13.7)0 (0)
FVC (% predicted)87.5 (72.0–101.0)91.0 (75.0–102.0)0.12990.0 (75.0–102.0)16(5.5)
DLCO (% predicted)62.8 (49.0–76.5)66.0 (52.0–79.0)0.45565.0 (50.0–79.0)31 (10.6)
Pulmonary hypertension, n (%)1 (1.5)19 (8.4)0.054†20 (6.8)1 (0.3)
Antitopoisomerase (anti-Scl70) (TOPO), n (%)30 (46.2)84 (38)0.252114 (39.9)7 (2.4)
Anti-RNA polymerase III (Pol3), n (%)14 (25.9)34 (18.5)0.24948 (20.2)55 (18.8)
Anticentromere (ACA), n (%)5 (7.7)14 (6.4)0.77719 (6.7)8 (2.7)
No autoantibodies (TOPO, Pol3 or ACA), n (%)7 (12.7)52 (28.4)0.02059 (24.8)55 (18.8)
  • Median (IQR) unless otherwise indicated.

  • P values refer to the Kruskal-Wallis (for continuous variables) or Fisher’s test (for categorical variables).

  • This table compares the distribution of patient characteristics at baseline between progressors and non-progressors, using the subset of 293 for whom the progression status is known. To distinguish between non-progressors and patients with insufficient data to describe their status, data requirements were set up. If progression was not detected using all data from the first >12±3 months, patients needed at least two data points to be considered non-progressors: one at baseline and another at least 5 months after baseline. Otherwise, we considered there were not enough data to ascertain their status. The 5-month limit was chosen so that all visits in the vicinity of the 6-month study mark could be counted.

  • †The presence of pulmonary hypertension was not included as a variable in prediction models for progression. Only one patient had pulmonary hypertension and progressed. Thus, a prediction model using mRSS, duration of skin thickening, an mRSS/duration interaction and the presence of pulmonary hypertension was too restrictive: no combinations of mRSS and duration of skin thickening enabled patients with pulmonary hypertension to progress.

  • DLCO, diffusing capacity for carbon monoxide; FVC, forced vital capacity; mRSS, modified Rodnan skin score.