CLINICAL EXPOSURE ASSESSMENT IN CHRONIC HYPERSENSITIVITY PNEUMONITIS: A DELPHI PROJECT

Abstract

SESSION TITLE: Wednesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM PURPOSE: Chronic hypersensitivity pneumonitis (CHP) is an immune mediated form of interstitial lung disease, caused by inhalational exposure to an environmental antigens, resulting in parenchymal fibrosis. Guidelines suggest a detailed history is taken to identify exposures to inducing antigens, but presently there are no validated tools to facilitate an evidence-based approach to this task. Technical variation in eliciting a history of antigen exposure may affect the frequency and confidence of CHP diagnosis. METHODS: A Delphi method was applied to an international panel of ILD experts, to obtain consensus regarding technique for the elicitation of exposure to relevant antigens from possible CHP patients. Items were derived from a systematic review of the literature. The consensus threshold was set at 80% agreement, and median ≥ 2 and IQR = 0. RESULTS: In two rounds, 36/40 experts participated. Themes included: possible CHP inducing exposures, features that contribute to an exposure’s relevance, quantification of a relevant exposure, and ancillary tests. Experts agreed on 21 exposure items to ask every patient with suspected CHP, including organic particulate matter: water damage/flooding, standing water, humidifiers/vaporisers/air conditioners, hot tubs/pools/spas, humid internal environment, visible and smelly mold, moldy hay/silage, moldy wood, organic matter (manure/compost), musical instruments (e.g. trombone/saxophone), metal working fluids; animal and plant proteins: birds, down or feather products, vegetable production including mushroom workers, food production (i.e. salami, cheese, popcorn, wheat, sugarcane, malt, other); and chemical exposures: isocyanates, and exposure to vapours, dusts, gases, mists, or fumes. A minimum relevant duration of exposure required was agreed to be 1-12 months, and a temporal relationship between exposure and onset of symptoms and improvement on exposure avoidance increased the likelihood the exposure was linked to disease. A positive antibody test was agreed to increase the diagnostic likelihood of CHP, but was not considered a requirement for diagnosis. Consensus was unable to be reached in the dose/quantification of exposure, nor the use of an occupational hygienist. CONCLUSIONS: This Delphi survey provides items that ILD experts agree are important to ask in all patients presenting with suspected CHP. CLINICAL IMPLICATIONS: Ongoing research is required to validate these items in the clinical setting. DISCLOSURES: No relevant relationships by Hayley Barnes, source=Web Response No relevant relationships by Harold Collard, source=Web Response No relevant relationships by Ian Glaspole, source=Web Response No relevant relationships by Phil Molyneaux, source=Web Response No relevant relationships by Julie Morisset, source=Web Response No relevant relationships by Glen Westall, source=Web Response