E038 Predictors for pulmonary function decline in interstitial lung disease

Abstract

Abstract Background/Aims Interstitial lung disease (ILD) is commonly associated with a decline in forced vital capacity (FVC). The most substantial loss of lung function typically occurs early in the course of the disease. The natural history of ILD varies among individuals. Several studies have employed FVC decline as the primary endpoint and NICE has recently approved antifibrotics based on this as an endpoint. An FVC reduction exceeding 10% has consistently been shown to correlate with poorer survival, leading to evidence-based guidelines recommending, an absolute decrease in FVC of 10% can be used as a surrogate marker of mortality. Aim: To obtain insights into the decline in lung function in patients with ILD, by comparing FVC measurements at baseline and 52 weeks. We hypothesised that the rate of absolute decline is increased with higher age, active smoking, sex, duration of ILD and comorbidities. Methods This was a retrospective study conducted at Southend University Hospital, involving a single-centre cohort of ILD patients identified from the ILD multidisciplinary team from 2016-June 2023. Data collection included parameters such as age at ILD onset, gender, occupation, smoking history, serial pulmonary function tests, imaging, comorbidities, survival outcomes, causes of death, and treatment regimens. Results Data from 197 patients were included in this study. Mean age of the cohort at diagnosis was 74. Men 112 (57%) and females 85 (43%). Among the study population 128 had a history of ex or current smoking. Mean duration of ILD was 40 months, ranging from 2 to 168 months. Of the participants 115 were deceased & 83 remained alive. We included most common conditions in the analysis: idiopathic pulmonary fibrosis (IPF) = 65, RA = 22, idiopathic pulmonary fibrosis with autoimmune features (IPAF) =15, hypersensitivity pneumonitis (HP) = 20, unclassified=25, SSc-ILD = 13, Sjogren’s = 2, myositis = 1, vasculitis = 3 and sarcoidosis = 7. For analysis, we included RA, SSc, Sjogren’s, vasculitis, ankylosing spondylitis, myositis, and sarcoidosis in the CTD -ILD group. 23 were excluded from analysis (COOP, OP, CPFE, PPFE and drug induced pneumonitis). We categorised disease progression as severe, if FVC decline exceeded 10%. This was achieved as follows; 3/36 in CTD -ILD, 2/10 in IPAF, 6/16 in HP, 5/19 unclassified in ILD and 14/47 in IPF (χ²=7.5, p = 0.109). Moderate disease progression was defined as an FVC decline between 5- 10%. It was achieved in 6/36 in CTD -ILD, 3/16 in HP, 1/19 in unclassified and 5/47 in IPF (χ²=3.8, p = 0.439).In univariate analysis, none of the predictors achieved significance for severe or moderate progression among subgroups. In multivariate analysis, only the disease subgroup achieved significance in predicting significant lung function decline progression. Conclusion The rate of decline in lung function during follow-up differed across the subgroups based on clinical factors and demographics. This data supports the unpredictable nature of ILD. Disclosure G.M. Koduri: Corporate appointments; NONE. Consultancies; NONE. Shareholder/stock ownership; NONE. Royalties; NONE. Honoraria; NONE. Member of speakers’ bureau; NONE. Grants/research support; NONE. Other; NONE.