Univariate and multivariate analyses of the associations of anti-CCP2 positivity with the RA-ILD.

Univariate and multivariate associations of anti-CCP2 with the occurrence of RA-ILD was conducted by logistic regression with a backward stepwise model. Covariates in multivariate model included gender, age, disease duration, smoking, medication, and other CTD complication. β: partial regression coefficient; DMARDs: disease-modifying antirheumatic drugs; Anti-CCP2: anti-citrullinated peptide antibody; COR: crude odds ratio; AOR: adjusted odds ratio; 95% CI: 95% confidence interval. Three equal groups of low, moderate and high positive anti-CCP2 were defined as 25.0≤anti-CCP2