Conflict of interest: D.M.G. Halpin reports personal fees from AstraZeneca, Chiesi, GlaxoSmithKline and Pfizer, and personal fees and non-financial support from Boehringer Ingelheim and Novartis, outside the submitted work. Conflict of interest: B.R. Celli reports grants and other from Astra Zeneca (research site), personal fees from GlaxoSmithKline (consulting and scientific committee), and personal fees from Boehringer Ingelheim, Novartis, Sanofi-Aventis and Menarini (all for consulting), outside the submitted work. Conflict of interest: G.J. Criner has nothing to disclose. Conflict of interest: P. Frith reports personal fees from Boehringer Ingelheim, Menarini and Novartis (travel compensation and speaker fees), non-financial support from Global Initiative for Chronic Obstructive Lung Disease (travel reimbursement for Board meetings), and non-financial support from Lung Foundation Australia (travel support to Board meetings), outside the submitted work. Conflict of interest: M.V. López Varela has nothing to disclose. Conflict of interest: S. Salvi has nothing to disclose. Conflict of interest: C.F. Vogelmeier reports personal fees from Almirall, Cipla, Berlin Chemie/Menarini, CSL Behring, and Teva; grants and personal fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Grifols, Mundipharma, Novartis, and Takeda; grants from German Federal Ministry of Education and Research (BMBF) Competence Network Asthma and COPD (ASCONET), Bayer Schering Pharma AG, MSD, and Pfizer, all outside the submitted work. Conflict of interest: R. Chen reports grants and personal fees from GSK, Astra-Zeneca and Boehringer-Ingelheim, and personal fees from Novartis, during the conduct of the study. Conflict of interest: K. Mortimer reports personal fees from the International Union Against TB and Lung Disease, outside the submitted work. Conflict of interest: M. Montes de Oca has nothing to disclose. Conflict of interest: Z. Aisanov has nothing to disclose. Conflict of interest: D. Obaseki has nothing to disclose. Conflict of interest: R. Decker has nothing to disclose. Conflict of interest: A. Agusti reports personal fees from AstraZeneca, Chiesi and Nuvaira, and grants and personal fees from Menarini and GSK, outside the submitted work.