P5 How should patients with interstitial lung abnormalities be evaluated and monitored? Experience from a secondary care interstitial lung disease clinic

through lowdose computed tomography (LDCT) screening reduces lung cancer mortality. Undiagnosed interstitial lung disease (ILD) can be incidentally detected on LDCT, but whether this leads to improved clinical outcomes is unclear. Methods The West London lung screening pilot invited eversmokers aged 55–75 for a lung health check, and LDCT for those meeting a prespecified lung cancer risk score. LDCTs were reported by 5 consultant thoracic radiologists with 8 years thoracic CT experience. Participants without known ILD and with (i) >10% interstitial lung abnormalities (ILAs) as defined by the Fleischner Society on LDCT (ii) 5–10% ILAs on LDCT and restrictive spirometry (pre-March 2020), (iii) ILAs >5% (without spirometry post-March 2020), (iv) progressive ILAs on serial imaging performed after 12–24 months, were referred for clinical evaluation to the ILD Unit at the Royal Brompton Hospital. Diagnoses were assigned after multidisciplinary team (MDT) discussion. Results ILAs of >5% extent on LDCT were identified in 39/ 1853 (2.1%) subjects screened between August 2018 and April 2021 (table 1). Respiratory symptoms were present in 18/39 (46.1%) and crackles were auscultated in 17 of 22 subjects (77.3%) undergoing physical examination. Past exposure to potential environmental triggers was noted in 21/39 (53.8%). Diagnostic bronchoalveolar lavage was performed in 7/39 (17.9%) and one patient underwent transbronchial lung cryobiopsy. After MDT discussion, ILD was concluded in 31/39 (79.5%) cases, of which 14/31 (45.2%) were diagnosed with IPF. In the IPF subgroup, antifibrotics were initiated in 7/14 (50%) of cases. In those diagnosed with other ILDs, immunomodulatory treatment was initiated in 2/25 (8%) subjects. Conclusion A large proportion of individuals with newly identified ILAs have an abnormal clinical examination and respiratory symptoms, consistent with the widely held suspicion that ILD is underdiagnosed in the community. Lung cancer screening in this demographic provides a unique opportunity to address this unmet health metric. Earlier identification of ILD, specifically IPF, allows institution of antifibrotic therapies proven to modify the natural history of the disease by preserving lung function and extending life. The cost-effectiveness of this approach for ILD screening warrants detailed evaluation.