Ab1210 Comprehensive Analysis of Clinical Features in Established Systemic Sclerosis Interstitial Lung Disease

Background: Interstitial lung disease (ILD) stands as the primary cause of mortality in patients with Systemic Sclerosis (SSc). Despite the identification of several risk factors to develop ILD in SSc, limited research has been directed towards understanding their impact on the progression of established SSc-ILD. Objectives: This study aims to evaluate the clinical characteristics of SSc patients with ILD and to compare features between those experiencing progressive lung function decline and those without such progression. Methods: We conducted a retrospective study on a cohort of 415 SSc patients. Inclusion criteria required the confirmation of ILD by HRCT. Demographic, clinical, analytical and pulmonary function tests (PFT's) parameters before and after ILD onset were collected. Statistical significance was set at p-valuesResults: 64 patients with SSc-ILD were included, most of them females (93.8%) with a mean age at diagnosis of 60.5 years. Limited SSc was observed in 59.4%, and the predominant specific autoantibody was the anti-topoisomerase (28.1%). Table 1 summarizes the patient's characteristics. Follow-up revealed a significant decline in FVC in all patients since SSc onset (2.80±0.7 vs 2.16±0.76, p=0.000) and after ILD detection (2.37±0.69 vs 2.16±0.76, p=0.000). Male sex was associated with worse %FVC at SSc-ILD onset, persisting throughout follow-up and leading to poor lung function outcomes. However, no significant differences were found in FVC decline based on clinical SSc subset (limited vs. diffuse) or SSc autoantibodies (ATA vs. ACA) after ILD onset. Smoking history, digital ulcers, and pulmonary hypertension were associated with poor lung function outcomes. No significant differences were observed in other clinical features such as myositis, arthritis, gastrointestinal involvement, renal crisis, or cancer. Rheumatoid factor (RF) positivity was associated with poorer pulmonary function after ILD diagnosis (p=0.034). The presence of a UIP pattern did not correlate with worse lung function at the onset of ILD or at follow-up, when compared to non-UIP patterns. Among the twenty-four patients who received ILD treatment, both %FVC and ml-FVC outcomes worsened, with no significant differences noted in DLCO. Conclusion: Worse lung function outcomes after SSc-ILD onset were associated to male sex, smoking history, digital ulcers, pulmonary hypertension, and RF positivity. Notably, in contrast to patients at risk of developing SSc-ILD, no significant differences were observed based on SSc subset or SSc autoantibodies in patients with established ILD. Early volume decline was observed during follow-up, even before ILD onset, in all patients within our cohort. We did not find that treatment prevents pulmonary function decline. It could be explained by the inclusion of patients with unfavorable prognosis factors and the retrospective nature of the analysis. Prospective, multicentric studies to comprehensively assess risk factors for poor prognosis and the progression SSc-ILD patients are needed. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.