Competing Interests: Conflict of interest: M. Miravitlles has received speaker fees from AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, Menarini, Kamada, Takeda, Zambon, CSL Behring, Specialty Therapeutics, Janssen, Grifols and Novartis, consulting fees from AstraZeneca, Atriva Therapeutics, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, CSL Behring, Inhibrx, Ferrer, Menarini, Mereo Biopharma, Spin Therapeutics, ONO Pharma, Palobiofarma SL, Takeda, Novartis, Novo Nordisk, Sanofi, Zambon and Grifols and research grants from Grifols. A.M. Turner has received either grants or speaker fees from AstraZeneca, GlaxoSmithKline, Boehringer Ingelheim, Chiesi, CSL Behring, Takeda, Vertex and Grifols Biotherapeutics. M. Torres-Duran has received speaker fees from Chiesi, CSL Behring, Grifols and Resmed and consulting fees from CSL Behring and Grifols. J.L. López-Campos has received honoraria during the last 3 years for lecturing, scientific advice, participation in clinical studies or writing for publications for (alphabetical order): AstraZeneca, Boehringer Ingelheim, Chiesi, CSL Behring, Esteve, Ferrer, Gebro, GlaxoSmithKline, Grifols, Menarini, Novartis, Rovi, and Teva. J.L. Rodríguez-Hermosa has received speaker fees from Zambon, Bial, Gebro Pharma, GlaxoSmithKline, Chiesi, Boehringer Ingelheim, CSL Behring and Grifols. J.M. Hernández-Pérez has received speaker fees from Grifols, CSL Behring, Astra-Zeneca, GSK, Bial laboratory, Teva laboratory, support for attending meetings from Grifols, CSL Behring, and consulting fees from CSL Behring. F. Casas-Maldonado has received speaker fees from AstraZeneca, Bial, Boehringer Ingelheim, Chiesi, Gebro Pharma, GlaxoSmithKline, Laboratorios Esteve, Laboratorios Ferrer, Menarini, Novartis, Rovi, TEVA, VERTEX, Zambon, CSL Behring and Grifols and consulting fees from AstraZeneca, Chiesi, GlaxoSmithKline, CSL Behring and Grifols. M. Barrecheguren has received speaker fees from Grifols, Menarini, CSL Behring, GSK, Boehringer Ingelheim and consulting fees from GSK, Novartis, CSL Behring and Boehringer Ingelheim. A. Bustamante has received speaker fees from Boehringer Ingelheim, AstraZeneca, GSK, Novartis and Ferrer, and funding for traveling or attending meetings from CSL Behring, AstraZeneca and Chiesi. C. González has received speaker fees from, Menarini, GSK, Novartis, Boehringer Ingelheim and Chiesi. C. Rodríguez-García has received speaker fees from GSK, AstraZeneca, Grifols, Chiesi, Ferrer, Menarini and Boehringer Ingelheim, expert testimony for Chiesi, support for attending meetings from FAES. C. Esquinas has received speaker fees from CSL Behring. C.F. Clarenbach received advisory fees from Roche, Novartis, Boehringer, GSK, Astra Zeneca, Sanofi, Vifor, OM Pharma, CSL Behring, Grifols, Daiichi Sankyo and MSD. C. Guimaraes reports support for the present manuscript from CSL Behring. C. Martinez-González reports lecture honoraria from Boehringer Ingelheim, Zambon; travel support from Roche; leadership role with SEPAR; outside the submitted work. A. Hecimovic reports lecture honoraria from Boehringer Ingelheim, Roche, MSD, Providens, CSL Behring; travel support from Boehringer Ingelheim, Roche; advisory board participation from Boehringer Ingelheim; outside the submitted work. W. Janssens reports grants from AstraZeneca and Chiesi Pharmaceuticals; consulting fees from AstraZeneca and Griphols; lecture honoraria from Chiesi, AZ, GSK; 3 KUL patents on pulmonary function tests; roles as Board Member – past president BERS, chair of Flemish Society for Tuberculosis and Tobacco Prevention; shareholder and co-founder of ArtiQ (AI spinoff company of KU Leuven); outside the submitted work. B. Lara reports travel support from ERS, supporting the present work. J. Stolk reports grants from CSL Behring, Kamada Ltd; outside the submitted work. The remaining authors report no conflicts of interest.