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

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.