Conflict of interest: P.M. O'Byrne reports personal fees for membership of the Joint Oversight Board for LABA safety study; consultancy fees from AstraZeneca, GSK, Chiesi and Covis; and grants/grants pending from AstraZeneca, Genentech, Novartis, Merck and Bayer. Conflict of interest: I.D. Pavord reports personal fees and other from AstraZeneca (speaker's honoraria for sponsored meetings; payments for organising educational events; honoraria for attending advisory panels; sponsorship to attend international scientific meetings), Boehringer Ingelheim (speaker's honoraria for sponsored meetings; honoraria for attending advisory panels; sponsorship to attend international scientific meetings), Teva (speaker's honoraria for sponsored meetings; payments for organising educational events; honoraria for attending advisory panels; sponsorship to attend international scientific meetings) and from GSK (speaker's honoraria for sponsored meetings; payments for organising educational events; honoraria for attending advisory panels; payments to support FDA approval meetings; sponsorship to attend international scientific meetings); grants, personal fees and other from Chiesi (speaker's honoraria for sponsored meetings; honoraria for attending advisory panels; sponsorship to attend international scientific meetings; research grant); personal fees from Aerocrine (speaker's honoraria for sponsored meetings), Almirall (speaker's honoraria for sponsored meetings), Novartis (speaker's honoraria for sponsored meetings; honoraria for attending advisory panels), Sanofi/Regeneron (speaker's honoraria for sponsored meetings; payments for organising educational events; honoraria for attending advisory panels), Genentech (honoraria for attending advisory panels), Merck (honoraria for attending advisory panels; co-patent holder of the rights to the Leicester Cough Questionnaire and has received payments from Merck for its use in clinical trials), Circassia (honoraria for attending advisory panels), Knopp (honoraria for attending advisory panels), Bayer (co-patent holder of the rights to the Leicester Cough Questionnaire and has received payments from Bayer for its use in clinical trials) and from Insmed (co-patent holder of the rights to the Leicester Cough Questionnaire and has received payments from Insmed for its use in clinical trials), outside the submitted work.