Table 1. Characteristics of 556 autoantibody RA patient participants in CLEAR I (longitudinal evaluation of early RA) and CLEAR II (cross-sectional evaluation of established RA).

Significant differences in demographic parameters between study groups were tested with T-tests for independent samples (Age at RA, Disease duration) and normal approximations for testing differences between large sample proportions (remaining variables). P-values for these tests are listed in the right column. Where data was unavailable for some of the subjects, sample sizes showing the numbers of subjects available for analysis are shown within the table

	CLEAR I (n=228)	CLEAR II (n=328)	P value
Age at RA onset, mean (SD)	48.8 (13.4)	43.4 (14.0)	<0.0001
Disease duration at enrollment, months (SD)	12.8 (7.3)	133.8 (112.7)	<0.0001
Gender (female), %	84.2	83.5 (N = 324)	0.83
Anti-CCP antibodies, % positive	85.1	87.1 (N = 271)	0.52
Rheumatoid factor, % positive	95.7 (N = 211)	96.6 (N = 322)	0.62
Both CCP and RF positive (%)	80.6 (N = 211)	82.6 (N = 265)	0.56
HLA SE positive (%)	45.9 (N = 218)	39.5 (N = 258)	0.16
Smoker (current) (%)	29.8	25.3	0.24
Smoker (ever) (%)	52.2	54.6	0.58