POS0839 DecreaSSc: AN OBSERVATIONAL STUDY TO ASSESS THE VALIDITY OF HOME MONITORING TO DETECT PROGRESSION OF INTERSTITIAL LUNG DISEASE IN SYSTEMIC SCLEROSIS

Background: Timely detection of progression of interstitial lung disease (ILD) in systemic sclerosis(SSc) is warranted to start or intensify treatment to halt disease progression[1]. Home spirometry, enabling frequent monitoring, can potentially identify progressive disease earlier[2]. Objectives: To assess the validity of home monitoring to detect progressive SSc-ILD. Methods: Forty-three adult SSc patients, from our ongoing DecreaSSc study, fulfilling ACR-EULAR criteria, with a disease-duration ≤ 5 years and maximum 8 weeks immunotherapy are included. Patients performed weekly home spirometry (forced vital capacity(FVC)) using a Bluetooth-enabled handheld spirometer for one year. Results were collected through a mobile application. During semi-annual study visits, patients performed pulmonary function testing(PFT) in the hospital. This interim analysis focuses on patients with 6 month's follow-up data. Pearson correlation coefficients between home and hospital measurements at baseline and 6 months was calculated. Next, we performed regression analyses with FVC as dependent variable for each individual patient to estimate the absolute decline in FVC% assessed by home spirometry at 6 months. Based on this estimated decline, the sensitivity and specificity of home spirometry to detect progression of SSc-ILD (defined as 5% decline in FVC (yes/no)) was assessed using the change in hospital PFT as gold standard. Results: Twenty-five patients completed 6 months follow-up, with a mean(SD) age of 59(11) years, 54% being female, 35% having dcSSc and a mean(SD) disease duration of 1.5(1.2) years. The mean(SD) FVC% predicted at baseline based on the hospital PFT was 91(13)%. During the study, 9 patients were initiated on immunomodulation. A strong correlation between home and hospital measurements was observed at baseline (r=0.90, p<0.001) and at 6 months (r= 0.85, p=<0.001) (FSigure 1, for examples). The mean(SD) change in FVC % predicted estimated with linear regression analysis for the home measurements was -1.7(5.8)% and the change in FVC% predicted in the hospital measurements was -0.32(5.8)%. Five patients showed disagreement between hospital and home measurements for a decline of 5% in FVC (Table 1). The sensitivity of home spirometry to detect progression of SSc-ILD was 75%(95% CI 58-92%) and the specificity was 81% (95% CI 66-96%). Conclusion: These preliminary data indicate that home spirometry might be a valid tool to monitor lung function and to detect progressive SSc-ILD. REFERENCES: [1] Hoffmann-Vold AM et al. Curr Opin Pulm Med. 2022;28(5):441-7. [2] Wijsenbeek MS et al. Lancet Respir Med. 2023;11(1):97-110. Acknowledgements: NIL. Disclosure of Interests: Arthiha Velauthapillai: None declared, C. Moor Grants and other from Boehringer Ingelheim, Astra Zeneca and Daiichi Sankyo, outside the submitted work, paid to the institution., Jeska K. de Vries-Bouwstra received consulting fees from Abbvie, Janssen and Boehringer Ingelheim., received research grants from Roche, Galapagos Janssen, NVLE and ReumaNederland; all payments were made to her institution., Marlies Wijsenbeek consulting or speaker fees from AstraZeneca, BI, Bristol Myers Squibb, CSL Behring, Galapagos, Galecto, Hoffmann-La Roche, Horizon Therapeutics, Kinevant Sciences, Molecure, NeRRe, Novartis, PureTech, Thyron, Trevi, Vicore., from The Dutch Pulmonary Fibrosis Patients Association, The Dutch Lung Foundation, The Netherlands Organisation for Health Research and Development, The Thorax Foundation, Sarcoidosis.nl, AstraZeneca/DaiichiSankyo, Boehringer Ingelheim (BI), Hoffmann-La Roche., C.H.M. van den Ende: None declared, Madelon Vonk Boehringer Ingelheim, GSK, Janssen, MSD, Novartis, Boehringer Ingelheim, Janssen , Unrestricted research grants from Boehringer Ingelheim, Ferrer and Galapagos.