Abstract Rationale While “idiopathic” denotes the “I” in IPF, vapor, gas, dust, or fumes (VGDF) are known risk factors for pulmonary fibrosis. However establishing a casualty relationship poses a significant challenge, primarily attributed to the absence of validated diagnostic tools. We aimed to evaluate the use of induced sputum as part of occupational evaluation in patients with UIP pattern and relevant exposures. Methods 22 patients with a multidisciplinary discussion (MDD)-confirmed diagnosis of IPF were included:13 with occupational exposure to asbestos, silica, metals or vapor/gas (occupational PF OPF) and 9 without known exposure (IPF). All completed a detailed exposure questionnaire and underwent induced sputum collection for cytology, Lactate dehydrogenase(LDH) analysis, and metal content using X-ray fluorescence (XRF). Results Study groups were comparable in demographics, smoking status, and IPF-related parameters. The mean age at diagnosis was 69.5±2.5 years, with an average follow-up of 2.6 years; most patients received antifibrotic therapy (18/23, 78%). The most common exposure among OPF patients was to silica/metal dust (8/13, 61.5%), with a mean exposure duration of 35.9±16.8 years. OPF patients showed a higher macrophage percentage (19%±12.2 vs. 9%±8.2, p = 0.037) and more frequent intracellular non-organic particles (11/13 vs. 0/10, p = 0.0009). LDH levels were undetectable in all OPF samples, compared to a mean of 18.7±9.7 U/L in IPF (p = 0.0002). No differences were found in metal types or levels. Smoking status was not associated with any clinical or sputum characteristics. Conclusions Patients with a UIP pattern and occupational exposures demonstrate differences in sputum composition. Induced sputum analysis may aid in establishing a causal link between exposure and pulmonary fibrosis. Further large-scale studies are warranted to validate these results This abstract is funded by: None
Klein et al. (Fri,) studied this question.