Critical analysis of spirometric patterns in correlation to chest computed tomography among adult Indigenous Australians with chronic airway diseases

ABSTRACT

Background: There is sparse literature evidence in the spirometric patterns of adult Indigenous Australians with and without chest computed tomography (CT)-proven chronic airway diseases (CADs).Methods: Participants spirometry testing graded as acceptable for quality and had a chest CT scan showing radiographic evidence of CADs were included for analysis.Results: Of the 1350 spirometric tests performed between 2012 and 2020, a total of 212 patients with a mean age of 53 years and 54% females were eligible to be included. One-third (30%) had normal chest CT (without CADs), 35% had predominant COPD, 19% bronchiectasis and 16% combined COPD and bronchiectasis. Percentage predicted values for forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁) both pre- and post- bronchodilator were significantly reduced for all participants – FVC: CT-normal 64%, 65%; COPD 58%, 62%; bronchiectasis 54%, 54%; combined COPD and bronchiectasis 50%, 53%. FEV₁: CT-normal 62%, 65%; COPD 46%, 49%; bronchiectasis 48%,51%; combined COPD and bronchiectasis 36%,40%. FEV₁/FVC was only reduced for CT abnormality patients – CT-normal 96%,98%; COPD 77%,77%; bronchiectasis 87%,89%; combined COPD and bronchiectasis 71%,72%.Conclusions: Restrictive spirometric pattern is common and an obstructive pattern with COPD, in isolation or when COPD coexists with bronchiectasis.

KEYWORDS:

• Aboriginal
• bronchiectasis
• chronic obstructive pulmonary disease
• computed tomography
• forced vital capacity
• First Nations
• Indigenous
• lung function test
• pulmonary function test
• spirometry

Abbreviation’s list

BDR: Bronchodilator responsiveness

BMI: Body mass index

CAD: Chronic airway disease

COPD: Chronic obstructive pulmonary disease

CI: Confidence interval

CT: Computed tomography

FEV₁: Forced expiratory volume in one second

FVC: Forced vital capacity

IQR: Interquartile range

LLN: Lower limit of normal

NHANES-III: Third National Health and Nutrition Examination Survey

NT: Northern territory

OR: Odds ratios

TEHS: Top End Health Service

Acknowledgments

The authors sincerely thank all the respiratory technologists and Respiratory Clinical Nurse Consultants from Darwin Respiratory and Sleep health and Royal Darwin Hospital, Darwin Private Hospital, Darwin, Australia, for their invaluable contribution toward this study. The authors thank Mr Xinlin Jing, Health Information Services, Royal Darwin Hospital, Darwin, Northern Territory, Australia for helping with data collection for this study. The authors also extend their sincere gratitude to their research assistant, Mrs Joy J Mingi, Department of Public Health, Charles Darwin University, Darwin, Northern Territory, Australia and special thanks to Ms Ara Joy Perez from Darwin Respiratory and Sleep health, Darwin Private Hospital, Darwin, Australia for her invaluable contribution toward this study. The authors also extend their sincere appreciation to our Indigenous health workers.

Author contributions

In this study, all authors were involved in the conception and design, analysis and interpretation of the data; the drafting of the paper or revising it critically for intellectual content; and the final approval of the version to be published; and that all authors agree to be accountable for all aspects of the work.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplementary material

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Additional information

Funding

This paper was not funded.