POS0839 DecreaSSc: AN OBSERVATIONAL STUDY TO ASSESS THE VALIDITY OF HOME MONITORING TO DETECT PROGRESSION OF INTERSTITIAL LUNG DISEASE IN SYSTEMIC SCLEROSIS (2024)

Abstract

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.

Acknowledgements: NIL.