AB1429 PERSISTENT INFLAMMATION AND PULMONARY FUNCTION CHANGES PREDICT PROGRESSIVE FIBROSING INTERSTITIAL LUNG DISEASES DEVELOPMENT IN RHEUMATIC PATIENTS

Abstract

BackgroundThe progressive fibrosing interstitial lung disease (PF-ILD) remains a challenge for clinical care. Studies reported that fibrosis-predominant pattern on high-resolution computed tomography (HRCT) and a worse baseline pulmonary function tests were associated with a progression to PF-ILD 1. Whether the inflammatory marker changes predict PF-ILD development was unknown.ObjectivesTo evaluate prognostic values of the early inflammatory markers and the pulmonary function tests of developing PF-ILD in patients with connective tissue disease-related interstitial lung disease (CTD-ILD) and interstitial pneumonia with autoimmune features (IPAF).MethodsThis was a retrospective, single-center study. The patients with CTD-ILD and IPAF were included. The PF-ILD was identified at two years after the ILD diagnosis, as according to the INBUILD study 2. The ILD patterns on the HRCT and the pulmonary function tests at diagnosis and one year after ILD diagnosis were reviewed by three pulmonologists independently. The baseline demographics, autoimmune manifestations, and serology at diagnosis, three months, and one year after ILD diagnosis were collected. The data were analyzed using the R version 4.1.2.ResultsFrom 2010 to 2020, we enrolled 34 patients into the analysis. These included 11 patients with Sjogren’s syndrome, 7 patients with idiopathic inflammatory myopathy, 3 patients with mixed connective tissue diseases, 1 patient with systemic sclerosis, and 14 patients with IPAF. The HRCT patterns were usual interstitial pneumonia in 13, non-specific interstitial pneumonia (NSIP) in 8, organizing pneumonia (OP) in 6, and lymphocytic interstitial pneumonia (LIP) in 1.At 2 years, 15 patients developed PF-ILD. The CTD diagnoses and the radiographic patterns at diagnosis were not associated with the development of PF-ILD. The predicted functional vital capacity (FVC) at diagnosis (80% vs. 69%, p=0.047), diffusion capacity of the lung for carbon monoxide (DLCO) at diagnosis (76% vs. 44%, p = 0.021), FVC at one year (94% vs. 68%, p = 0.047), and DLCO at one year (68% vs. 36%, p = 0.018) were associated with the PF-ILD progression. Immunologically, the PF-ILD patients had a borderline higher 1-hour erythrocyte sediment rate (ESR) at baseline (36 vs. 22 mm/h, p = 0.051), but the difference became prominent after 3 months (38 vs. 10 mm/h, p = 0.023), and 12 months (28 vs. 8 mm/h, p = 0.005) after the ILD diagnosis. (Figure 1)Figure 1.Change of erythrocyte sediment rate at 1 hour over time. ESR, erythrocyte sediment rate at 1 hour. ILD, interstitial lung disease. PF-ILD, progressive fibrosing interstitial lung disease. * p < 0.05, ** p < 0.01ConclusionThe higher ESR during the first one year after ILD diagnosis was associated with the progression to PF-ILD. In serial pulmonary function tests, both the FVC and DLCO at baseline were associated with PF-ILD, and the between-group differences were more prominent at 1 year of follow up. The findings suggest that the persistent inflammation might contribute to the progressive worsening of pulmonary fibrosis and subsequent lung function decline. The immunology and pulmonary function parameters at one year predict the development of PF-ILD.