Fibrotic Interstitial Lung Disease Early Recognition and Strategic Therapy Study in China (FIRST): protocol for a prospective, multicentre registry study.

INTRODUCTION: Interstitial lung diseases (ILDs) are a heterogeneous group of diseases characterised by varying degrees of inflammation and fibrosis. Among these, fibrotic interstitial lung disease (FILD) is receiving increasing attention. Many questions remain about FILD, such as identifying which ILDs are likely to progress to FILD, the timing of such progression, early recognition methods and biomarkers for FILD recognition and progression, highlighting the urgent need for a large multicentre FILD cohort to advance relevant studies. METHODS AND ANALYSIS: The Fibrotic Interstitial Lung Disease Early Recognition and Strategic Therapy Study in China (FIRST) study is a prospective, multicentre cohort study of FILD conducted across 40 hospitals/centres in China, aiming to reveal clinical phenotype and further integrate multidimensional data to develop prediction models for fibrosis progression. The study will enrol more than 10 000 patients, using existing national ILD cohorts, and will collect comprehensive clinical, imaging, histological and biological data to support histopathological, imaging and biomarker-related studies. The primary outcome is fibrosis progression within 12 months, with secondary outcomes including the natural history, mortality, comorbidities and treatment conditions of FILD, using a standardised data collection and follow-up approach supported by an Electronic Data Capture system. ETHICS AND DISSEMINATION: The study's protocol has undergone a thorough review and received approval from the Ethics Committee of China-Japan Friendship Hospital and the other participating sites currently enrolling patients. The findings of the study will be shared with the broader scientific community through publication in peer-reviewed journals. TRIAL REGISTRATION: NCT06655090; Pre-results.