Footnotes

• Contributors All authors contributed to the manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests JJF had speaker and consultant fees with GlaxoSmithKline, Novartis, TEVA, Lundbeck, Solvay, Abbott, Bial, Merck-Serono, Grunenthal and Merck Sharp and Dohme. FJP had consultant and speaker fees with Astra Zeneca, Bayer, Boehringer Ingelheim, and Daiichi Sankyo. DC and JC do not have any competing interests to disclose.

• Patient consent Not required.

• Provenance and peer review Not commissioned; externally peer reviewed.