Among patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD), abatacept was linked to better outcomes, including a lower risk for mortality, hospitalization, or mechanical ventilation, than rituximab.

"This large, real-world target-trial emulation strengthens the evidence that abatacept may offer a more favorable outcome than rituximab in RA-ILD, with consistently lower risks of all-cause mortality across the subgroup and sensitivity analyses. By providing the first head-to-head comparison of these two biologics, the study provides a critical evidence gap in RA-ILD management," the authors wrote.

The study was led by Po-Cheng Shih, MD, Chung Shan Medical University, Taichung, Taiwan. It was published online on July 22, 2025, in Arthritis & Rheumatology.

Despite extensive matching, residual confounding by indication and unmeasured factors (eg, detailed smoking history, RA activity scores, and imaging-based ILD severity) may have existed. ILD diagnoses relied on diagnostic codes without direct radiologic or full pulmonary function confirmation, which may have led to misclassification. As this was a retrospective observational US-based study, causality could not be definitively established, and the findings may not be generalizable to other settings internationally.

No funding was received for this study. The authors reported having no relevant conflicts of interest.