Pos0043 Rate of Severe and Fatal Infections in a Cohort of Patients With Rheumatoid Arthritis-Associated Interstitial Lung Disease. A Prospective Multicenter Study

Background: RA-associated interstitial lung disease (RA-ILD) is a common pulmonary manifestation with high morbidity and mortality, and infection plays a significant role in exacerbations and mortality in RA-ILD patients. Objectives: To describe severe infection, foci of infection, microorganisms, associated factors, and impact on mortality in patients with rheumatoid arthritis–associated interstitial lung disease (RA-ILD) 1,2. Methods: A prospective multicentric cohort of patients with RA-ILD followed from 2015 to 2023. The primary variable was incident severe infection and mortality due to infection. The main outcome measures were incident severe infection and fatal infection. Fatal infection was defined as a death in which infection played a key role, either immediately or within 30 days following the last admission for infection. Infectious foci were evaluated. Incidence Rates (IR) for infection and mortality were calculated per 100 person-years (p-y), and 3 multivariate models were conducted to explore factors associated with the first infection, total infections, and mortality. Results: One hundred forty-eight RA-ILD patients were followed for a median of 56.7 months (699.3 person-years) (Table 1). During this time, 142 patients (96%) experienced at least one infection, with 368 different infectious episodes recorded, yielding an incidence rate of 52.6 per 100 person-years. The median (IQR) time to first infection was 21.2 (8.0 – 45.2) months (Figure 1A). Patients who suffered mortality due to infections, compared to other patients (i.e., those who continued living or died of other causes), had a higher number of prior infections and higher infection rates (IR 95%CI 84.39 68.34 – 100.46 per 100 person-years vs. 45.74 40.20 – 51.28 per 100 person-years; IRR 95%CI 1.84 1.48 – 2.30) (Figure 1B). Of the 48 deceased patients, 65% died due to infections. Pulmonary infections predominated as the first infection (74%), total infections (74%), and mortality (80%), with frequent agents including SARS-CoV-2, S. pneumoniae, P. aeruginosa, and Influenza virus A (Table 2). The three Cox multivariate models (first infection, number of infections, and mortality) were consistent, highlighting that age, inflammatory activity by DAS28, and treatment with glucocorticoids and immunosuppressants are prominent factors in the infectious risk and mortality of RA-ILD patients. Regarding pulmonary status, the duration of RA-ILD and the degree of DLCO impairment were important. Conclusion: Patients with RA-ILD have a high risk of serious infection, especially respiratory infection. Infection develops early, is recurrent, and is frequently fatal. The presence of associated factors such as advanced age, joint inflammation, and treatment highlight the importance of integrated and preventive medical care. REFERENCES: 1 Kim H, Cho S-K, Lee J, Bae S-C, Sung Y-K. Increased risk of opportunistic infection in early rheumatoid arthritis. Int J Rheum Dis. 2019 Jul;22(7):1239–46. 2 Atzeni F, Masala IF, di Franco M, Sarzi-Puttini P. Infections in rheumatoid arthritis. Curr Opin Rheumatol. 2017 Jul;29(4):323–30. Acknowledgements: NIL. Disclosure of Interests: None declared.