Clinical Characteristics Of Patients With Asthma COPD Overlap (ACO) In Australian Primary Care

Abstract

Purpose

Many older adults with a history of smoking and asthma develop clinical features of both asthma and COPD, an entity sometimes called asthma-COPD overlap (ACO). Patients with ACO may be at higher risk of poor health outcomes than those with asthma or COPD alone. However, understanding of ACO is limited in the primary care setting and more information is needed to better inform patient management. We aimed to compare the characteristics of patients with ACO or COPD in Australian general practices.

Patients and methods

Data were from the RADICALS (Review of Airway Dysfunction and Interdisciplinary Community-based care of Adult Long-term Smokers) trial, an intervention study of an interdisciplinary community-based model of care. Baseline demographic and clinical characteristics, pre- and post-bronchodilator spirometry, dyspnoea and St. George’s Respiratory Questionnaire scores were compared between 60 ACO patients and 212 with COPD alone.

Results

Pre-bronchodilator Forced Expiratory Volume in 1 second (mean±SD 58.4±14.3 vs 67.5±20.1% predicted) and Forced Vital Capacity (mean 82.1±16.9 v 91.9±17.2% predicted) were significantly lower in the ACO group (p<0.001), but no difference was found in post-bronchodilator spirometry. Demographic and clinical characteristics, dyspnoea, quality of life, comorbidities and treatment prescribed did not differ significantly between groups.

Conclusion

This is the first study describing the clinical characteristics of ACO patients in Australian general practices. Our finding of lower pre-bronchodilator lung function in the ACO group compared to those with COPD reinforces the importance of spirometry in primary care to inform management.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12614001155684.

Keywords:

• asthma
• chronic obstructive pulmonary disease
• primary care
• spirometry

Acknowledgments

This trial was funded by the National Health and Medical Research Council (NHMRC) through the NHMRC Partnerships for Better Health – Partnership Projects initiative (APP1076255). Cash and in-kind contributions were received from our partner organisations, Lung Foundation Australia (LFA), Boehringer Ingelheim, and Eastern Melbourne PHN (EMPHN). The LFA and EMPHN were involved in project design and conduct and contributed to data analysis and writing of manuscripts. Boehringer Ingelheim was involved in project discussions, planning and progress review, but had no involvement in the design of the intervention program, and did not contribute to decisions about data analysis and the dissemination of findings. Billie Bonevski was supported by an NHMRC Career Development Fellowship (GNT1063206) and a Faculty of Health and Medicine, University of Newcastle, Gladys M. Brawn Career Development Fellowship. Jenifer Liang received the Cyril Tonkin Scholarship 2014, administered by the Victorian College of Pharmacy Foundation Board, Monash University. We thank Denise van den Bosch (contributions to project management and data extraction), Narelle Cox and all research assistants, students, clinics and participants. Interim findings from this paper were presented at the Thoracic Society of Australia & New Zealand Annual Scientific Meeting on the Gold Coast in 2019 as an oral presentation. The presentation abstract was published in TSANZSRS Conference Abstracts in Respirology 2019 Mar;24 Suppl 1:4-206. doi: 10.1111/resp.13491.

Author Contributions

The RADICALS trial was designed, and funding obtained by JG, GMR, AEH, NAZ, BB, AM, PE, KP and MJA. Data were collected and managed under the supervision of JG, JL and SW. This analysis of baseline data for ACO was planned by MJA, GI, VT and JG. Statistical analysis was conducted by MJA, VT and EP. The findings were interpreted, and the first draft written by GI, VT and MJA. All authors contributed to drafting and revising the manuscript and approved the final version for publication. MJA and JG act as guarantors, and all authors agree to be accountable for those aspects of the work within their areas of expertise.

Disclosure

Michael J Abramson holds an investigator-initiated grant from Pfizer for unrelated research. He has also conducted an unrelated consultancy for Sanofi and reports grants from Boehringer-Ingelheim, during the conduct of the study. Johnson George has held investigator-initiated grants from Pfizer for unrelated research and has received cash and in-kind contributions from Boehringer Ingelheim (BI) Pty Ltd for an unrelated project. He has received an honorarium from GSK for consultancy. He also received non-financial support from the Lung Foundation Australia, grants from the National Health and Medical Research Council, non-financial support from the Inner East Melbourne Primary Health Network, during the conduct of the study and grants and personal fees from GSK and grants from Pfizer, outside the submitted work. Professor Anne E Holland reports grants from the National Health and Medical Research Council, grants from Boehringer Ingelheim, non-financial support from Lung Foundation Australia, and non-financial support from Eastern Melbourne PHN, during the conduct of the study. Ms Jenifer Liang reports grants and non-financial support from Boehringer Ingelheim, non-financial support from the Lung Foundation Australia, non-financial support from Eastern Melbourne PHN, and grants from National Health and Medical Research Council (Australia), during the conduct of the study. The authors report no other conflicts of interest in this work.