LAUSR

BACKGROUND The majority of Indigenous Australians reside in non-urban locations, with reduced access to chest radiology such as Computed Tomography (CT). Spirometry and Chest X-Ray (CXR) may be used in the absence of CT, however the correlation of spirometry indices to CT defined chronic airway diseases (i.e.COPD and bronchiectasis) against CXR among Indigenous people is sparsely reported. AIM To evaluate spirometry indices against CXR and CT findings among adult Indigenous Australians. METHODS Indigenous patients who had undergone a spirometry test between 2012 and 2020 and had a CXR or chest CT scan assessed for presence(+ )/absence(- ) of airway diseases were included in this study. RESULTS Of 643 patients (57%female, 31% remote/very remote), 364 (57%) had CT&CXR available. Patients who were "CT- &CXR- " for airway diseases (48%) recorded a mean FVC, FEV1 and FEV1 /FVC of 61%, 59%&0.76 compared to 57%, 49%&0.66 in the "CT+ &CXR- " group, and 53%, 39%&0.58 in the "CT+ &CXR+ " group. CXR showed sensitivity (44%) and specificity (88%), while spirometry showed 62%&77% compared to CT. Spirometry demonstrated predominately restrictive impairment among "CT- &CXR- ", and mixed/obstructive impairment among "CT+ &CXR- " and "CT+ &CXR+ " groups. CONCLUSION Indigenous Australians tend to demonstrate restrictive impairment in the absence of radiological evidence of airway disease. However, in the presence of airway disease, combinations of mixed and obstructive impairments were common. Obstructive impairment shows greater sensitivity for identifying COPD than that shown by CXR, however; CXR shows greater specificity. Hence, spirometry in conjunction with chest radiology should be utilised to aid in the assessment of airway diseases in this population. This article is protected by copyright. All rights reserved.