Determinants and Follow-up of Lung Function Data from a Predominantly First Nations Cohort of Adults Referred to Specialist Respiratory Outreach Clinics in Regional and Remote Queensland

Purpose Northern Territory (NT)-based clinical service data suggest substantial lung function impairment amongst First Nations adults as young as 18-40 years. Our objectives were to describe the burden of disease and lung function of adults living in regional-remote Queensland, identify determinants of lung function, and evaluate the impact of a specialist respiratory outreach service on lung function. Methods Retrospective 8-year cohort study (February 2012-March 2020) of 1113 First Nations Australian adults (and 648 non-First Nations adults) referred to respiratory outreach clinics in regional-remote Queensland. Results In the combined cohort, the forced expiratory volume in 1 s (FEV1) was clinically abnormal for 54% of First Nations patients (51% of non-First Nations patients), forced vital capacity (FVC) for 46% (36%), FEV1/FVC% for 30% (36%), and gas diffusing capacity (DLCO) for 44% (37%). A respiratory diagnosis was assigned by a respiratory physician in 78% of First Nations (76% non-First Nations) patients. Smoking, household smoke exposure, underweight BMI, and respiratory disease were associated with reduced lung function. In the 40% of patients (709/1765) followed up, FEV1 and FVC significantly improved (mean change: zFEV1 = 0.15 [95% CI 0.10-0.20]; zFVC = 0.25 [0.20, 0.31]), and FEV1/FVC% significantly reduced (mean = - 0.10 [95%CI - 0.07 to - 0.03]), with no significant change in DLCO. Patients with COPD had lower FEV1 improvement, whilst underweight and obese patients had lower FVC improvement. Conclusion Regional-remote First Nations adult Queenslanders have higher lung function than previously reported, with no lung function decline observed at follow-up visit, including for those with respiratory disease.