Pos0668 a Fibrotic Pattern on High Resolution Chest Computed Tomography Predicts Increased Mortality in Rheumatoid Arthritis- Associated Interstitial Lung Disease: A Retrospective Cohort Study

Background: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is one of the most common extra-articular manifestations of RA, associated with high morbidity and mortality. Median survival after RA-ILD diagnosis varies among studies, but is markedly reduced compared to RA patients without ILD and the general population. Objectives: To calculate mortality rate of RA-ILD and evaluate its association with different ILD radiographic patterns and comorbidities in the 'Attikon' cohort. Methods: Retrospective chart review was performed to analyze the clinical, laboratory and radiological characteristics of patients with RA-ILD. Overall survival from ILD diagnosis until death, as well as comparison of survival between usual interstitial pneumonia (UIP) and non-specific interstitial pneumonia (NSIP) groups, were examined with Kaplan-Meier curves and log-rank test. A multivariate Cox proportional hazards model was also applied to compare survival between NSIP and UIP, adjusted for age, sex, and comorbidities (through Rheumatic Disease Comorbidity Index, RDCI), from both first ILD diagnosis and first visit in our center until last visit or death. Results: 81 RA-ILD patients were included (66.7% female, mean age at ILD diagnosis 69.7(SD 9.5) years, with median follow-up in our cohort 3.6 (IQR 1.6-5.1), median follow-up to death 3.2 (IQR 1.0-4.2) and median time to death from ILD diagnosis 3.6 (IQR 2.2-5.2). NSIP was the most frequent radiologic pattern (63%), followed by UIP (30.9%). Mean FVC% predicted and DLCO% predicted at ILD diagnosis was 81.2 (SD 18) and 56.6 (SD 20.8), respectively. Overall mortality (cumulative incidence) at the end of follow-up was 29.6% (n= 24/81) while probability of survival fell to 50% at 8.6 years (103 months, Figure 1). Patients with UIP exhibited significanly worse survival compared to NSIP patients(Logrank test, p: 0.03, Figure 2). Also, higher mortality rates were observed between UIP and NSIP patients in the Cox model (HR: 3.23, p: 0.01). RDCI, sex and age were not associated with increased mortality rates in our cohort. Conclusion: A UIP pattern in HRCT (High Resolution Chest Computed Tomography) confers a significantly increased risk for death compared to NSIP pattern in patients with RA-ILD. Comorbidities, age and sex do not significantly contribute tot he excess of mortality in our cohort REFERENCES: 1 Antonella Laria et al, Interstitial Lung Disease in Rheumatoid Arthritis: A Practical Review, Front. Med., 13 May 2022 2 HJ Farquhar et al, Survival of adults with rheumatoid arthritis associated interstitial lung disease - A systematic review and meta-analysis, Semin Arthritis Rheum 2023 Jun:60:152187 3 Maria A. Nieto et al, Mortality rate in rheumatoid arthritis-related interstitial lung disease: the role of radiographic patterns, BMC Pulm Med (2021) 21:205 4 Mir Sohail Fazeli et al, Rheumatoid arthritis-associated interstitial lung disease: epidemiology, risk/prognostic factors, and treatment landscape, Clin Exp Rheumatol 2021 Sep-Oct;39(5):1108-1118 5 Sicong Huang et al, Rheumatoid arthritis-associated interstitial lung disease: Current update on prevalence,risk factors, and pharmacologic treatment, Curr Treatm Opt Rheumatol. 2020 Dec; 6(4): 337-353 Acknowledgements: NIL. Disclosure of Interests: None declared.