Competing Interests: Conflict of interest: R.E. Morty reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; and is ERS Fellowships and Awards Director (2016–2019). Conflict of interest: L.E. Donnelly reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; grants from AstraZeneca and Boehringer Ingelheim, outside the submitted work; and is ERS Fellowships and Awards Director-Elect. Conflict of interest: D. Stolz reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; grants from AstraZeneca AG, Pan Gas AG, Weimann AG, Curetis AG, Boston Scientific AG, Circassia Pharmaceuticals and Lungenliga Switzerland, personal fees from AstraZeneca AG, Novartis AG, GSK AG, Roche AG, Zambon, Pfizer, Schwabe Pharma AG, Sanofi and Vifor AG, outside the submitted work; and is Education Council Chair ERS 2017–2020. Conflict of interest: N. Roche reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; and is ERS Guidelines Director (2018–2021). Conflict of interest: T. Welte reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; and is ERS President (2018–2019). Conflict of interest: K.A. Forrest reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; and is an employee of ERS. Conflict of interest: C.E. Brightling reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; and is ERS CRC Director (2016–2019) and ERS Science Council Chair-Elect. Conflict of interest: G.G. Brusselle reports grants from European Union (EU), co-funding for joint ERS/EMBO fellowships from the European Molecular Biology Organization (EMBO), co-funding for joint ERS/TTS fellowships from the Turkish Thoracic Society (TTS), co-funding for joint ERS/ICS fellowships from the Indian Chest Society (ICS), co-funding for joint ERS/ALAT fellowships from Asociación Latinoamericana de Tórax (ALAT), co-funding for joint ERS/DZL fellowships from the German Center for Lung Research (Deutsches Zentrum für Lungenforschung; DZL), co-funding for joint ERS/SEPAR fellowships from Sociedad Española de Neumología y Cirugía Torácica (SEPAR), co-funding for joint ERS/SPLF fellowships from the Société de Pneumologie de Langue Française (SPLF), grants for funding and hosting ERS fellowship in industry from Novartis, training partnerships with National Institute for Health and Care Excellence (NICE UK) and Cochrane Iberoamerica - Spain, funding for joint fellowships from The Union Against TB and Lung Disease, co-funding for the joint Emiel F.M. Wouters fellowship from CIRO, during the conduct of the study; and is ERS Science Council Chair (2016–2019).