6MWD 6-min walk distance 6MWT 6-min walk test 1-AT 1-antitrypsin 1-ATD 1-antitrypsin deficiency ACOS Asthma–COPD overlap syndrome AECOPD Acute exacerbations of COPD AHR Airway hyperresponsiveness BMI Body mass index BODE BMI, airflow obstruction, dyspnoea, exercise capacity CF Cystic fibrosis COPD Chronic obstructive pulmonary disease CRP C-reactive protein CT Computed tomography DLCO Diffusing capacity of the lung for carbon monoxide FEF25–75% Forced expiratory flow at 25–75% of FVC FeNO Exhaled nitric oxide fraction FEV1 Forced expiratory volume in 1 s FFM Fat-free mass FVC Forced vital capacity HRCT High-resolution computed tomography ICS Inhaled corticosteroid IL Interleukin ILD Interstitial lung disease KCO Transfer coefficient of the lung for carbon monoxide MRI Magnetic resonance imaging PET Positron emission tomography PR Pulmonary rehabilitation PPM Potentially pathogenic microorganism QALYs Quality-adjusted life-years TNF Tumour necrosis factor List of abbreviations