Footnotes

• Contributors TC-T was involved in the study concept, acquisition of data, interpretation of data and writing of the manuscript. IL involved in the acquisition of data and critical revision of the manuscript. JAA-D and JO were involved in the interpretation of data and critical revision of the manuscript for important intellectual content. ALdM was involved in the study concept, interpretation of data and critical revision of the manuscript for important intellectual content.

• Competing interests TC-T has received travel expenses for attending meetings from Biogen-Idec, Merck and Novartis. JO has received honoraria as a consultant on the scientific advisory board of Biogen-Idec, Genzyme and Novartis, and also for his participation in meetings, as an organiser, speaker or moderator, as well as for his participation in clinical trials or research projects promoted by Allmirall, Bayer, Biogen—Idec, Merck, Novartis and Teva pharmaceuticals.

• Patient consent Obtained.

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

• Data sharing statement All relevant data were included in this study.