ILD-India registry: Idiopathic pulmonary fibrosis (IPF) and connective tissue disease (CTD) associated interstitial lung disease (CTD-ILD)

Abstract

Background: Little is known about the profile of Interstitial Lung Diseases (ILDs) in India. Aim: Describe prevalence and characteristics of patients with newly diagnosed IPF and CTD-ILD in India. Methods: Prospective registry with detailed case report forms gathered from 27 centers in 19 cities across India. All patients had CTD serologies and high-resolution computed tomography (HRCT) chest. Results: The final diagnosis validated by multidisciplinary discussion (MDD) among ILD experts at Center for ILD (CILD), University of Washington, Seattle, USA was IPF (per 2011 criteria) in 148/1084(14%)and CTD-ILD in 151/1084(14%)adult patients. Kappa score for interobserver agreement on IPF and CTD-ILD diagnoses between CILD experts and local investigators was 0.38. Patients with CTD-ILD were younger (51±14yrs) than those with IPF (65±8 yrs) and more often women (74% CTD-ILD vs 26% IPF. 44% of IPF patients were current smokers, compared to 13% with CTD-ILD.29% of CTD-ILD patients had definite usual interstitial pneumonia on HRCT.Mean FVC and DLCO were moderately reduced (FVC 58% predicted in both groups, DLCO 67% CTD-ILD 64% IPF). The most common CTD associated with ILD was rheumatoid arthritis (25%). Conclusions: Our findings provide the first prospective insight into the clinical features and proportion of patients with new onset IPF and CTD-ILD in India; data for IPF in the ILD-India registry was limited to patients with typical clinical/HRCT features of IPF. Interobserver agreement on diagnosis between CILD experts and local site investigators was fair and supports the need for MDD among experienced ILD experts for an accurate diagnosis.