MUC1 and interstitial lung disease: Thirteen factors, including demographic variables, clinical risk factors (such as arthritis onset, clinical disease activity index—CDAI, and disease activity score—DAS28 scores), serum proteins (ACPA, KL-6, matrixmetaloproteinase 13-MMP13, and C-X-C motif chemokine 11-CSCL11/I-TAC), and preexisting treatments (corticosteroid and disease-modifying antirheumatic drugs—DMARDSs), were associated with RA-ILD progression.