RT Journal Article SR Electronic T1 The role of calcium metabolism assessment in the clinical setting of interstitial lung diseases JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA706 DO 10.1183/13993003.congress-2021.PA706 VO 58 IS suppl 65 A1 Paolo Cameli A1 Carla Caffarelli A1 Miriana D'Alessandro A1 Laura Bergantini A1 Martina Armati A1 Maria Dea Tomai Pitinca A1 Piersante Sestini A1 Stefano Gonnelli A1 Elena Bargagli YR 2021 UL http://erj.ersjournals.com/content/58/suppl_65/PA706.abstract AB Background: Hypercalcemia and hypercalciuria are common in sarcoidosis and have been associated with active disease. No evidence is available on the specificity of these alterations among different interstitial lung diseases (ILDs).Aim of the study: We investigated the specificity of calcium metabolism biomarkers among patients affected with sarcoidosis, idiopathic pulmonary fibrosis (IPF) and fibrotic hypersensitivity pneumonitis (fHP).Methods: We retrospectively enrolled patients with sarcoidosis, IPF and fHP followed at the ILD Referral Centre in Siena. To be included in the study, availability of serum and urinary assessment of calcium metabolism, as well as clinical, radiological and functional data, was mandatory.Results: We recruited 305 patients (237 sarcoidosis, 40 IPF and 28 fHP). Sarcoidosis patients showed significantly higher serum and urinary calcium than IPF and fHP patients (p=0.0004 and p<0.0001, respectively); this trend was confirmed comparing fibrotic sarcoidosis (17 patients, 7.2%) with IPF and fHP patients (p=0.0237 and p=0.0138, respectively). Urinary calcium showed the best diagnostic accuracy in discriminating sarcoid and non-sarcoid lung fibrosis (AUC 0.7658; p = 0.0026) (Fig.1).Conclusions: Our results suggest that dysregulation of calcium metabolism is a specific feature of sarcoid granulomas and that urinary calcium assessment may be useful in the clinical management of fibrotic ILDs.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA706.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).