Ab1192 Prevalence, Risk Factors, and Outcomes of Systemic Sclerosis-Associated Interstitial Lung Disease in Chinese: A Multi-Centred Cohort Study

Background: Interstitial lung disease (ILD) is one of the leading causes of death in systemic sclerosis (SSc) and can have a significant impact on a patient's quality of life 1. Identification of at-risk patients can enable timely monitoring and intervention. Ethnic disparity is prevalent in SSc and there are variable data on SSc-ILD in Chinese 2. Objectives: To investigate the prevalence, risk factors of development, and outcomes of ILD in Chinese SSc patients. Methods: This was a multi-centred retrospective cohort study of SSc patients attended our rheumatology clinics from 2008-2022. SSc patients fulfilled the 2013 ACR/EULAR criteria were included. Patients with overlap syndrome and non-Chinese ethnicity were excluded. The cohort was categorised in to SSc patients with ILD and SSc patients without ILD. Those with ILD was further divided into patients with or without progressive ILD according to high-resolution computed tomography and pulmonary function test findings. Risk factors for the development of ILD identified from previous literature were used as covariates. Univariate and multivariate analyses were performed to compare SSc patients among different subgroups to identify associative factors. Results: The cohort included 223 SSc patients with median follow-up time of 8.1 years (IQR: 4.0-14.2 years). The prevalence of ILD was 49.8% (111/223). The baseline characteristics of patients are shown in Table 1. SSc patients with ILD were more likely to have diffuse cutaneous involvement (with ILD: 39.6%, without ILD: 16.1%) and carry the anti-topoisomerase antibody (with ILD: 57.7%, without ILD: 20.5%). Multivariate analysis showed history of crackles (HR 2.813, p=0.001) was the independent factor associated with ILD development. Among patients with ILD, 64.1% (59/92) had progressive disease. C-reactive protein (CRP) level at ILD diagnosis (HR 1.064, p=0.002) was identified as an independent predictor for ILD progression. The overall mortality rate was 24.2% (54/223), with 29.7% (33/111) in SSc-ILD patients and 18.8% (21/112) in SSc patients without ILD (Figure 1). The most common cause of death was pneumonia/ILD, accounting for 64.8% (35/54). Predictors of mortality included age of SSc diagnosis (HR 1.101, p=0.002), history of smoking (HR 5.173, p=0.028), and baseline CRP (HR1.103, p=0.009). Conclusion: In this cohort of Chinese SSc patients, ILD was prevalent, with the majority showing disease progression. CRP level can be utilised as both a predictor of ILD progression and mortality. Older age at SSc diagnosis and history of smoking were also identified as predictors of mortality. These findings emphasise the importance of early detection and management of ILD, and may help risk stratification in Chinese SSc patients. REFERENCES: 1 Elhai M, Meune C, Boubaya M, Avouac J, Hachulla E, Balbir-Gurman A, et al. Mapping and predicting mortality from systemic sclerosis. Ann Rheum Dis. 2017;76(11):1897-905. 2 Chan DTH, So H. Systemic Sclerosis-Associated Interstitial Lung Disease: Prevalence and Risk Factors. Journal of Clinical Rheumatology and Immunology. 2023;23(01):15-24. Acknowledgements: NIL. Disclosure of Interests: None declared.