Immunosuppressive medication patterns in rheumatoid arthritis-associated interstitial lung disease by antifibrotic...

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a serious pulmonary manifestation for which multidisciplinary ILD teams balance immunomodulation with antifibrotic therapy. The 2023 ACR/CHEST guideline recommends immunosuppressive therapy as first-line treatment for autoimmune ILD, but real-world agent-level documentation alongside antifibrotic therapy is poorly characterized. We characterized immunosuppressive medication documentation among seropositive RA-ILD patients stratified by antifibrotic documentation status.

Using a federated U.S. EHR network (TriNetX, academic medical centers), we identified three cohorts of seropositive adults: RA without ILD (N = 31,932), coded RA-ILD without antifibrotic documentation (N = 1885), and coded RA-ILD with repeated antifibrotic documentation (N = 115). Immunosuppressive medications documented within 90 days of each patient's analytic index date were compared descriptively.

Methotrexate was documented in 52% of RA without ILD versus 12% of coded RA-ILD patients with repeated antifibrotic documentation. Azathioprine, mycophenolate, and rituximab were more frequently documented in coded RA-ILD. Among 98 coded RA-ILD patients with in-window antifibrotic documentation, 80.6% had at least one non-antifibrotic agent co-documented; 48 distinct medication sets were observed, with the most common set in 14.3% of patients.

Medication documentation among coded RA-ILD patients with repeated antifibrotic documentation was more heterogeneous than in RA without ILD, with no dominant medication set. Methotrexate documentation was uncommon, whereas azathioprine, mycophenolate, and rituximab were more frequently documented. These descriptive findings provide agent-level reference data for interdisciplinary management of RA-ILD and identify hypotheses for future comparative-effectiveness research; they do not establish treatment indication or comparative effectiveness.