Conflict of interest: R. Beasley reports grants and personal fees from AstraZeneca and Health Research Council of New Zealand, outside the submitted work. Conflict of interest: I. Braithwaite reports grants from AstraZeneca and Health Research Council of New Zealand, outside the submitted work. Conflict of interest: A. Semprini has nothing to disclose. Conflict of interest: C. Kearns has nothing to disclose. Conflict of interest: M. Weatherall has nothing to disclose. Conflict of interest: T. Harrison reports grants, personal fees and non-financial support from AstraZeneca, personal fees and non-financial support from GSK and Chiesi, outside the submitted work. Conflict of interest: A. Papi reports board membership, consultancy, payment for lectures, grants for research and travel expenses reimbursement from GlaxoSmithKline, AstraZeneca, Boehringer Ingelheim, Chiesi Farmaceutici and TEVA, board membership, consultancy, payment for lectures and travel expenses reimbursement from Mundipharma, Zambon, Novartis and Sanofi/Regeneron, grants for research, payment for lectures and travel expenses reimbursement from Menarini, personal fees for board membership, consultancy and travel expenses reimbursement from Roche, grants from Fondazione Maugeri and Fondazione Chiesi, personal fees for consultancy from Edmondpharma, outside the submitted work. Conflict of interest: I.D. Pavord reports personal fees for lectures, advisory board work, meeting attendance and educational activities from AstraZeneca, personal fees for lectures, advisory board work and meeting attendance from Boehringer Ingelheim and GlaxoSmithKline, personal fees for lectures from Aerocrine and Chiesi, personal fees for lectures and advisory board work from Almirall and Novartis, personal fees for advisory board work from Genentech, Regeneron, Sanofi, Circassia and Knopp, personal fees for lectures, meeting attendance and educational activities from Teva, grants from NIHR, outside the submitted work.