Impact of indoor exposure to particulate matter on the progression of idiopathic pulmonary fibrosis: a prospective multicentre cohort study protocol.

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease characterised by progressive fibrosis. Environmental exposures, including fine particulate matter (PM2.5), have been implicated in the progression of IPF; however, indoor data are limited. We aimed to evaluate the impact of indoor exposure to PM2.5 on the progression of IPF.

METHODS AND ANALYSIS: This prospective, multicentre cohort study involves 15 medical institutions across South Korea. A total of 120 patients with IPF have been recruited and will be followed for 1 year. The impact of indoor exposure to PM2.5 on clinical outcomes, including progression of the disease (defined as a relative decline in forced vital capacity ≥10% or diffusing capacity for carbon monoxide ≥15%), hospitalisation, acute exacerbations and mortality, will be assessed. Pulmonary function tests will be conducted quarterly at institutions, with home-based spirometry performed daily in a subset of 50 participants. The indoor PM2.5 level will be continuously measured using a scattering-based indoor air quality monitor (IAQ-CL; KWeather, Seoul, South Korea) and PM10, volatile organic compounds and carbon dioxide will also be measured. Biomarker analysis of Krebs von den Lungen-6 and other related markers will be performed. Statistical analyses will use linear mixed-effects models and time-to-event models to evaluate the association between exposure to PM and clinical and biomarker outcomes.

ETHICS AND DISSEMINATION: The study has been approved by the Institutional Review Boards of all institutions, including Asan Medical Center (S2021-1136-0051). Written informed consent was obtained from all participants prior to enrolment.

TRIAL REGISTRATION NUMBER: KCT0008638.