The ‘ABC’ of respiratory disorders among adult Indigenous people: asthma, bronchiectasis and COPD among Aboriginal Australians – a systematic review

BACKGROUND: Aboriginal Australians are reported to have higher presence of chronic respiratory diseases. However, comprehensive evidence surrounding this is sparse. Hence, a systematic review was undertaken to appraise the current state of knowledge on respiratory health in the adult Aboriginal Australians, in particular among the three most common respiratory disorders: asthma, bronchiectasis and chronic obstructive pulmonary disease (COPD). METHODS: A systematic review of primary literature published between January 2012 and October 2022, using the databases PubMed and Scopus, was conducted. Studies were included if they reported adult Aboriginal Australian prevalence’s or outcomes related to asthma, bronchiectasis or COPD, and excluded if adult data were not reported separately, if Aboriginal Australian data were not reported separately or if respiratory disorders were combined into a single group. Risk of bias was assessed by both Joanne Briggs Institute checklists and Hoys’ bias assessment. Summary data pertaining to prevalence, lung function, symptoms, sputum cultures and mortality for each of asthma, bronchiectasis and COPD were extracted from the included studies. RESULTS: Thirty-seven studies were included, involving approximately 33 364 participants (71% female). Eighteen studies reported on asthma, 21 on bronchiectasis and 30 on COPD. The majority of studies (94%) involved patients from hospitals or respiratory clinics and were retrospective in nature. Across studies, the estimated prevalence of asthma was 15.4%, bronchiectasis was 9.4% and COPD was 13.7%, although there was significant geographical variation. Only a minority of studies reported on clinical manifestations (n=7) or symptoms (n=4), and studies reporting on lung function parameters (n=17) showed significant impairment, in particular among those with concurrent bronchiectasis and COPD. Airway exacerbation frequency and hospital admission rates including mortality are high. DISCUSSION: Although risk of bias globally was assessed as low, and study quality as high, there was limited diversity of studies with most reporting on referred populations, and the majority originating from two centres in the Northern Territory. The states with the greatest Aboriginal Australian population (Victoria and New South Wales) reported the lowest number of studies and patients. This limits the generalisability of results to the wider Aboriginal Australian population due to significant environmental, cultural and socioeconomic variation across the population. Regardless, Aboriginal Australians appear to display a high prevalence, alongside quite advanced and complex chronic respiratory diseases. There is however significant heterogeneity of prevalence, risk factors and outcomes geographically and by patient population. Further collaborative efforts are required to address specific diagnostic and management pathways in order to close the health gap secondary to respiratory disorders in this population.