Epidemiology and clinical characteristics of interstitial lung disease in patients with rheumatoid arthritis from the JointMan database.

Interstitial lung disease (ILD) is a progressive fibrotic disease associated with rheumatoid arthritis (RA); real-world data for evaluating RA-associated ILD (RA-ILD) are limited. We evaluated prevalence, time to onset, clinical characteristics and prognostic factors in patients diagnosed with RA (n = 8963) in the Discus Analytics JointMan database (2009-2019) with and without ILD. ILD prevalence was 4.1% (95% confidence interval 3.7-4.5); > 90% had an ILD diagnosis after RA diagnosis (mean time to onset 3.3 years). At baseline, a higher proportion of patients with RA-ILD were older (> 65 years), male, with history of chronic obstructive pulmonary disease (COPD) compared with patients in the RA cohort. Patients in the RA-ILD cohort were likely to have more severe RA characteristics and joint evaluation compared with patients without ILD, at baseline and before/after ILD diagnosis. In this large, real-world database patients with (vs without) ILD had a higher burden of RA characteristics. Previously established risk factors for RA-ILD were confirmed (age, baseline COPD, anti-cyclic citrullinated peptide positivity, C-reactive protein, Clinical Disease Activity Index score); thus, recognition of these factors and tracking routine disease activity metrics may help identify patients at higher risk of RA complications and lead to improved diagnosis and earlier treatment.