Patient characteristics.
| Controls, n = 20 | IPF, n = 58 | SSc (exploratory set), n = 74 | SSc (test set), n = 212 | |
|---|---|---|---|---|
| Sex female, n (%) | 7 (35) | 14 (24.1) | 59 (79.7)*† | 165 (77.8) |
| Age, mean (SD) | 32.7 (6.3) | 61.1 (7.3)† | 51.4 (12.1)*† | 50.9 (12.6) |
| Smoking, current/former, n (%) | 0/0 | 4 (6.9)/37 (63.8)† | 4 (5.5)/28 (38.4)*† | 19 (9.2)/69 (33.3) |
| Followup, mo, median | — | 37.3 | 76.9* | 60.5 |
| Deceased, n (%) | ||||
| 3-year mortality | 19 (32.8) | 8 (10.8) | 28 (13) | |
| 5-year mortality | 34 (58.6) | 10 (13.5) | 43 (20.3) | |
| 15% DLCO decline*†, n (%)/ median mo | — | 39 (68.4)/14.5 | 34 (48.6)/34.5 | 90 (52.3)/41.3 |
| 10% FVC decline**, n (%)/ median mo | — | 43 (69.4)/14 | 30 (46.2)/34.8 | 84 (48.8)/39.5 |
| Progression-free survival**††, n (%)/median mo | — | 39 (72.2)/15.7 | 42 (57.5)/35 | 132 (71.4)/40.3 |
| Lung function, mean (SD) | ||||
| FVC, % predicted | — | 76.9 (22.6) | 80.3 (22.7) | 80.6 (23.2) |
| FEV1, % predicted | — | 79.4 (21.4) | 78.6 (20.0) | 78.2 (19.7) |
| DLCO, % predicted | — | 45.9 (16.8) | 56.2 (18.8)* | 53.6 (18.2) |
| CPI, mean (SD) | — | 47.3 (14.9) | 38.6 (17.4)* | 40.1 (16.4) |
| ATA/ACA antibodies, n (%) | — | 0 (0) | 31 (41.9)/11 (14.86)* | 89 (41.9)/33 (15.7) |
| ESR, mean (SD) | — | 19.2 (16) | 25.6 (22.6) | 24.3 (20.7) |
| dcSSc, n (%) | — | — | 26 (37) | 83 (40.1) |
| DTPA, mean (SD) | — | — | 44.7 (29.8) | 40.1 (25.2) |
↵* p < 0.05 vs IPF.
↵† vs controls.
↵** Measures were calculated in 172 patients for whom longitudinal lung function data were available from the time of serum collection, all with initial lung function testing within 6 months of serum collection.
↵†† Defined as the time to functional decline (of FVC and/or DLCO) or death. IPF: idiopathic pulmonary fibrosis; SSc: systemic sclerosis; CT: computed tomography scan; FVC: forced vital capacity; FEV1: forced expiratory volume 1 second; CPI: composite physiologic index18: dcSSc: diffuse cutaneous SSc; DTPA: 99mTc-technetium-labeled diethylene-triamine-pentacetate clearance; ATA: antitopoisomerase antibodies; ACA: anticentromere antibodies; ESR: erythrocyte sedimentation rate.