Abstract
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 6–12months. 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.
Key words: rheumatoid arthritis, interstitial lung disease, observational study, rituximab and prognosis

  Rheumatology 2020;59:2099–2108