Clinically Relevant Change in Airway Wall Thickness to Identify Disease Activity in COPD and Smokers At-Risk

<title>Extract</title> Chronic obstructive pulmonary disease (COPD) is characterised by heterogeneous airway inflammation and a variable clinical course [1]. Active airway inflammation can drive progressive structural and functional damage [1]. The concept of disease activity has therefore emerged as a framework to monitor disease progression and stability and to define attainable therapy targets [2]. However, quantifiable markers of disease activity beyond symptom burden, exacerbations, or lung function decline remain limited, particularly CT biomarkers of structural airway changes that are applicable across the full spectrum of smoking-related airway disease, including smokers at risk.