Table 1.

Baseline patient characteristics. Values are mean ± SD or n (%) unless otherwise specified.

Characteristics	All, n = 82	KL-6-positive, n = 29	KL-6-negative, n = 53	p
Age at disease onset, yrs	53.6 ± 11.0	53.6 ± 10.1	53.5 ± 11.5	0.88
Disease duration, yrs	2.4 ± 1.5	2.3 ± 1.4	2.4 ± 1.5	0.93
Male sex	18 (22)	8 (28)	10 (19)	0.36
African American	18 (22)	9 (31)	9 (17)	0.14
Disease type, diffuse	45 (55)	17 (59)	28 (53)	0.61
Immunosuppression	37 (45)	17 (59)	20 (38)	0.07
FVC% at baseline	75.2 ± 17.4	70.2 ± 14.4	77.9 ± 18.3	0.04
mRSS	16.7 ± 11.4	17 ± 10.5	16.5 ± 11.9	0.76
Anti-Scl 70	17 (21)	10 (35)	7 (14)	0.03
Anti-RNA polymerase III	20 (24.7)	5 (17)	15 (29)	0.29
Anticentromere	5 (6.2)	0 (0)	5 (10)	0.15

KL-6 positivity determined based on a level of 1273 U/ml. FVC%: % forced vital capacity; mRSS: Modified Rodnan skin score.