The Effects of Inhaled Airway Directed Pharmacotherapy on Decline in Lung Function Parameters Among Indigenous Australian Adults With and Without Underlying Airway Disease

Abstract

Background The trajectory of lung function decline among Indigenous patients with or without underlying chronic airway disease (COPD and concomitant bronchiectasis) and with use of inhaled pharmacotherapy, including inhaled corticosteroids (ICS), has not been reported in the past. Methods Adult Indigenous Australian patients identified to have undergone at least two or more lung function tests (LFTs) between 2012 and 2020 were assessed for changes in the lung function parameters (LFPs) between the first and last recorded LFTs. Results Of the total 1350 patients identified to have undergone LFTs, 965 were assessed to fulfil session quality, 115 (n=58 females) were eligible to be included with two or more LFTs. Among the 115 patients, 49% showed radiological evidence of airway diseases, and 77% were on airway directed inhaled pharmacotherapy. Median time between LFTs was 1.5 years (IQR 0.86,5.85), with no significant differences in LFPs noted between first and last LFT. Overall rate of change (mL/year) showed considerable variation for FVC (median −37.55 mL/year [IQR −159.88,92.67]) and FEV 1 (−18.74 mL/year [−102.49,71.44]) with minimal change in FEV 1 /FVC (0.00 ratio/year [−0.03,0.01]). When stratified by inhaled pharmacotherapy group, however, patients using ICS showed significantly greater rate of FEV 1 decline (−48.64 mL/year [−110.18,62.5]) compared to those using pharmacotherapy with no ICS (15.46 mL/year [−73.5,74.62]) and those using no pharmacotherapy (−5.76 mL/year [−63.19,67.34]) (p=0.022). Additionally, a greater proportion of these patients reached the threshold for excessive FEV 1 decline (64%) compared to those using pharmacotherapy without ICS (44%) and those using no pharmacotherapy (52%). Conclusion Decline in LFPs occurs commonly among adult Indigenous population, especially, excessive so among those using inhaled pharmacotherapy containing ICS.

Sex differences in pulmonary function parameters among Indigenous Australians with and without chronic airway disease

“…Varying manifestations of sex differences in PFTP’s have been demonstrated in this study, both with and without underlying radiological evidence of CADs among an Indigenous Australian cohort. This could also have implications in classifying severity of CADs [ 51 ] and in the clinical decision making while considering airway directed inhaled pharmacotherapy [ 52 ]. We believe the results represented in this study may be an avenue or encourage other researchers in characterising sex differences in other Indigenous populations, with a view to establishing normative reference lung function values for adult Indigenous population.…”

Implications of using the GLI-2012, GOLD and Australian COPD-X recommendations in assessing the severity of airflow limitation on spirometry among an Indigenous population with COPD: an Indigenous Australians perspective study

“…Furthermore, a recent study from our centre has shown significantly higher rates of excessive yearly FEV 1 decline among Indigenous patients on ICS, which may be due to higher prevalence of comorbid bronchiectasis. 31 Thus, the use of the COPD-X tool in this setting with no validated reference values along with higher prevalence of rather complex and concomitant respiratory comorbidities 11 has the potential to result in overprescription of ICS, which could be detrimental to patients outcomes.…”

COPD disease knowledge, self-awareness and reasons for hospital presentations among a predominately Indigenous Australian cohort: a study to explore preventable hospitalisation

“…There is sparse evidence in the literature addressing the utility and appropriate use of airway-directed inhaled pharmacotherapy among Indigenous patients with COPD. A recent study has demonstrated much higher yearly decline in forced expiratory volume in one second (FEV 1 ) among Indigenous patients prescribed ICS with airway disease 32. Although oral theophylline is recommended and could be considered in the management of patients with COPD,17 33 in this study, theophylline was noted to be prescribed very infrequently.…”

“…As such, it is plausible that the current study captured anywhere from 40% to 60% of current Indigenous COPD patients in the TEHS region. More recently, several aspects of respiratory health issues among Indigenous Australians from the TEHS region of the NT has been reported in the literature 19–24 28 32 35–40 52–66. Hence, this study could be considered as an important further step forward67 in addressing COPD disease awareness and knowledge in an Indigenous population.…”