O36. Rheumatoid-Arthritis-Related Interstitial Lung Disease: Association Between Biologic Therapy and Survival

Abstract

Background: RA is associated with clinically relevant interstitial lung disease (ILD) in approximately 5% of patients. Concern has been expressed over the use of biologic therapies in patients with RA-ILD, with several reports of disease progression and death from accelerated respiratory failure. We have examined the association between different biologic therapies and mortality in a large multi-centre group of patients retrospectively to determine any effect of these agents on survival. Methods: For the purposes of this study, we collected data from seven centres across the UK on patients with both RA and ILD (proved on HRCT) identified over a 12 year period from 2000 to 2012 using a standard proforma. We analysed the age, duration of both RA and ILD, outcome and, where appropriate, cause of death. Equivalent data were obtained from a control group of RA patients from one centre without lung disease, matched for age, sex and disease duration. We recorded the number of patients in each group receiving any biologic therapy. We compared both all cause and respiratory mortality between RA controls and patients with RA-ILD treated with and without biologics. In the biologic group, we compared those on anti- TNF therapies with those on Rituximab using Chi squared and relative risk calculators. Results: A total of 188 patients were identified from across the UK with proven RA-ILD. All cause (respiratory) mortality was 22% (10%) compared with controls 14% (6%) (P=0.07). Biologic therapy was prescribed to more RA-ILD patients (57) than RA controls (18), and these patients were older (P=0.02). The only significant difference in disease parameters between those on anti-TNF therapy and those on rituximab was an increase in usual interstitial pneumonia in the latter group (see Table 1). In spite of this, all cause (respiratory) mortality was higher in those receiving anti-TNF therapies at 31% (15%) than in those on rituximab at 8% (4%) (P=0.09). Conclusion: Patients with RA-ILD trend toward increased mortality compared with controls. They are more likely to receive biologic therapy, and such patients are older with longer disease duration. This large retrospective multi-centre study suggests a possible survival advantage in treating these patients with rituximab as opposed to anti- TNF therapy, both in terms of their all cause and respiratory mortality. This theory should be tested in a large prospective study.