Table 4.

Correlation of autoantibody reactivity against PAD2- and PAD4-citrullinated C1-INH with clinical features.

Clinical feature	ACPA reactivity against PAD2-citrullinated C1-INH		ACPA reactivity against PAD4-citrullinated C1-INH
	Correlation coefficient rs	p-Value	Correlation coefficient rs	p-Value
Age	−0.1053	0.2946	0.1755	0.0792
Sex	–	0.1851	–	0.9931
Disease duration	−0.0789	0.4332	0.3383	0.0005
Smoking	–	0.1509	–	0.5094
ACPA status	–	0.0036	–	<0.0001
RF status	–	0.3621	–	0.0022
CRP at sampling	0.2920	0.0034	0.1648	0.1031
ESR at sampling	0.2597	0.0094	0.1670	0.0984
DAS28	0.1588	0.1165	0.2743	0.006
HAQ	0.0757	0.4543	0.1692	0.0924
Cortisone treatment	–	0.9918	–	0.4793

For correlations with continuous variables, Spearman’s rank-order correlation test was used, and Spearman’s correlation coefficient r_s and the p-values are listed. For associations with categorical variables, Mann–Whitney U and Kruskal–Wallis rank-sum tests were used, and the p-values are listed. Significant p-values (p < 0.05) and corresponding correlation coefficients are highlighted in bold. ACPA, anti-citrullinated protein antibody; RF, rheumatoid factor; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; HAQ, health assessment questionnaire.