Case-Finding and Treatment Effects in COPD: Secondary Analysis of an Interdisciplinary Intervention Trial

Abstract

Background

US Preventive Services Taskforce recommends against screening for COPD in asymptomatic adults due to limited evidence on the efficacy of treatments for this population. However, global and Australian guidelines recommend a case-finding approach where those with symptoms and/or risk factors, including smoking, are screened. This study aims to explore patient characteristics by time of COPD diagnosis and the effectiveness of early treatment in those with or without symptoms.

Methods

Secondary analysis of a randomised controlled trial that included those with a pre-existing (n=130) or new diagnosis (n=142) of COPD. Those randomised to the intervention arm received an interdisciplinary intervention of smoking cessation support, home medicines review and home-based pulmonary rehabilitation, while controls received usual care. The primary outcome was health-related quality of life (HR-QoL) measured using St George’s Respiratory Questionnaire. To estimate the impact of early treatment, we compared the effectiveness of treatment versus control at 6- and 12-months for the new versus pre-existing diagnosis groups, and those symptomatic versus asymptomatic or minimally symptomatic based on COPD Assessment Test score.

Results

Approximately half of those newly diagnosed with COPD were already symptomatic. Early treatment in those diagnosed via case-finding had a positive non-significant impact on HR-QoL. The size of the treatment effects generally favoured the pre-existing diagnosis group when compared to case-finding and favoured those symptomatic when compared to those asymptomatic.

Conclusion

Despite useful insights into the impacts of case-finding and early treatments, this study, like most others, was not sufficiently powered. Further larger studies or combining sub-groups across studies are required.

Keywords:

• RCT
• screening
• interdisciplinary
• COPD

Abbreviations

AUD, Australia dollars; BD, bronchodilator; BMI, Body mass index; CAT, COPD Assessment Test; CI, confidence interval(s); CO, carbon monoxide; COPD, chronic obstructive lung disease; FEV₁, forced expiratory volume in 1 s; FEV₆, forced expiratory volume in 6 s; FVC, forced vital capacity; GOLD, Global initiative for Chronic Obstructive Lung Disease; GP, general practitioner; HADS, Hospital Anxiety and Depression Scale; HMR, home medicines review; HR-QoL, health-related quality of life; HSI, heaviness of smoking index; ITT, intention to treat; mMRC, modified Medical Research Council dyspnoea scale; N/A, not applicable; OD, odds ratio(s); PPA, per protocol analysis; RADICALS, Review of Airway Dysfunction and Interdisciplinary Community-Based Care of Adult Long-Term Smokers; RCT, randomised controlled trial; RTQ, readiness-to-quit; SD, standard deviation; SGRQ, St George’s Respiratory Questionnaire; USPSTF, US Preventive Services Task Force; VAS, visual analogue scale.

Data Sharing Statement

If interested, reasonable requests for data can be made to the corresponding author ([email protected]) and will be considered in line with the requirements of Monash University Human Research Ethics Committee approval (Project ID: 4899).

Acknowledgments

We wish to acknowledge and thank the RADICALS: chief investigators (Nicholas Zwar, Grant Russell, Billie Bonevski, Anne Holland, Eldho Paul, Sally Wilson and Ajay Mahal), the Data Safety and Monitoring Board members, the research staff and students, clinic staff and participants, and Brigitte Borg and The Alfred Respiratory Laboratory. We also acknowledge the RADICALS trial funders and partners (Boehringer Ingelheim, Eastern Melbourne PHN, Lung Foundation Australia and National Health & Medical Research Council). KP acknowledges the support of the Australian Government’s research training program.

Disclosure

KP was supported by an Australian Government Research Training Program (RTP) Scholarship. MJA holds investigator-initiated grants for unrelated research from Pfizer, Boehringer Ingelheim, Sanofi and GSK. He has also undertaken an unrelated consultancy (paid to his employer) for Sanofi and received a speaker’s fee from GSK. JG holds investigator-initiated grants for unrelated research from Pfizer, GSK and Boehringer Ingelheim. He has received honoraria (paid to his employer) from a consultancy for GSK, AZ and for invited presentations at a continuing education event organised by Pfizer. The authors report no other conflicts of interest in this work.