Efficacy of rituximab in slowing down progression of rheumatoid arthritis-related interstitial lung disease: data from the NEREA Registry.

OBJECTIVES: To asses the clinical course in RA-related interstitial lung disease (RA-ILD) patients with and without rituximab (RTX). The influence of other variables was also evaluated. METHODS: A longitudinal multicentre study was conducted in RA diagnosed with ILD from 2007 until 2018 in Madrid. Patients were included in a registry [pNEumology RhEumatology Autoinmune diseases (NEREA)] from the time of ILD diagnosis. The main endpoint was functional respiratory impairment (FI), when there was a decline ≥5% in the predicted forced vital capacity compared with the previous one. Pulmonary function was measured at baseline and in follow-up visits every 6-12 months. The independent variable was therapy with RTX. Covariables included sociodemographic, clinical, radiological and other therapies. Survival techniques were used to estimate the incidence rate (IR) and 95% CI of functional impairment, expressed per 100 patient-semesters. Cox multivariate regression models were run to examine the influence of RTX and other covariates on FI. Results were expressed as the hazard ratio (HR) and CI. RESULTS: A total of 68 patients were included. FI occurred in 42 patients [IR 23.5 (95% CI 19, 29.1)] and 50% of them had FI within 1.75 years of an ILD diagnosis. A multivariate analysis showed that RTX exposure resulted in a lower risk of FI compared with non-exposure [HR 0.51 (95% CI 0.31, 0.85)]. Interstitial pneumonia, glucocorticoids, disease activity and duration also influenced FI. CONCLUSION: RA-ILD patients deteriorate over time, with the median time free of impairment being <2 years. Patients exposed to RTX had a higher probability of remaining free of FI compared with other therapies. Other factors have also been identified.