Table 1.

Characteristics of subjects after stratification on anti-CCP titer.

	Low-titer anti-CCP (n =28)	Moderate-high titer anti-CCP (n =46)
Median age (range)	67 (20–85)	68 (36–84)
Female gender	18 (64%)	27 (59%)
History of cigarette smoking	16 (57%)	27 (59%)
Current cigarette smokers	3 (11%)	0
First degree relative with RA	3 (11%)	7 (15%)
RF positive	6 (21%)	16 (35%)
Median RF (range)	138 (25–1580)	148 (31–3650)
ANA ≥ 1:320	0	4 (9%)
Median anti-CCP (range)	24 (21–37)	100 (40–235)
Isolated airways disease	17 (61%)	23 (50%)
Isolated ILD	5 (18%)	5 (11%)
Airways disease and ILD	5 (18%)	14 (30%)
Combined pulmonary fibrosis with emphysema	1 (4%)	4 (1%)

ANA=anti-nuclear antibody, CCP=cyclic citrullinated peptide, RF=rheumatoid factor, and ILD=interstitial lung disease.