CO11 - Decline in Forced Vital Capacity and Survival in fibrotic Hypersensitivity Pneumonitis; Time to revisit the definition of Progressive Pulmonary Fibrosis guidelines?
E. Lynn (UK)1; J. Tadjkarimi (UK)1; A. Trachalaki (UK)1; E. Renzoni (UK)1; S. Bax (UK)1; R. Hewitt (UK)1; G. Jenkin (UK)1; P. George (UK)1; C. Stock (UK)1; A. Wells (UK)1;
1 - Interstitial Lung Disease Unit, Royal Brompton Hospital, Guy's & St Thomas' NHS Foundation Trust - London (United Kingdom);
Keywords: Progressive Pulmonary Fibrosis; Hypersensitivity Pneumonitis;
Select the theme: Progressive Pulmonary Fibrosis
Type: Original Papers
Presentation: Oral Communication

Introduction: Progressive Pulmonary Fibrosis (PPF) is defined by 2 of 3 criteria; worsening symptoms, radiological or physiological progression over 1 year in patients with Interstitial Lung Diseases (ILD) other than Idiopathic Pulmonary Fibrosis (IPF). Lung function decline is defined as an absolute decline in FVC > 5% predicted or in DLCO corrected >10% predicted within 1 year. The INBUILD study demonstrated the efficacy and safety of the use of Nintedanib in patients with fibrotic ILD. Real-world logistics have been recognised as a barrier in obtaining measurements at the required interval, potentially resulting in the undertreatment of patients who may benefit from antifibrotic therapy. 

Objectives: We assessed the association between survival and progression of disease in a cohort of patients with fibrotic HP.

Materials and Methods: Interrogating 7 years of data from a cohort of patients with fibrotic Hypersensitivity Pneumonitis (fHP). Progression was defined as relative decline of >10% in FVC as per INBUILD. Patients were grouped by time-to-first decline, either < 12 months (early), 12-30 months (late) or no decline at 30 months (stable). All-cause mortality was compared to time of decline in or stability of lung function and adjusted for age and composite physiological index.

Results: Of 267 patients 22% (n = 58) demonstrated FVC decline in less than 12 months, 24% (n = 64) at 12 – 30 months and 54% (n = 145) were stable. Mean age was 63 years (SD +/- 10.6 years) and baseline FVC was 77% predicted (SD +/- 22%). There was no difference in survival between early and late decliners though there was a difference in survival in early and late decliners compared to stable group. Combining early and late decliners, decline in FVC was round to be independently associated with higher mortality compared to those who remained stable (aHR 2.86, 95% ci 1.98-4.15; p < 0.0005)

Conclusions: Using a cohort of fibrotic HP patients, we demonstrate that in those with a relative decline of >10% in FVC display mortality similar over 12 and between 12 and 30 months decline. This is significantly higher compared to those with stable lung function. This suggests the need to revisit the 1 year timeline as defined by PPF criteria.