Received: 5 March 2021
Accepted: 14 May 2021
First Online: 22 June 2021
: Ethics committee approval was not required for anonymous retrospective data collection according to country regulations. All methods were carried out in accordance with relevant guidelines and regulations. All patients provided informed consent according to country regulations.
: Not applicable.
: M D’hooghe has received consultancy fees and congress support from Roche, Sanofi-Genzyme, Teva, Biogen, Merck-Serono, Bayer-Schering, Novartis and Allergan.V Popescu has received consultancy fees, educational and travel grants from Almirall, Biogen, Icometrix, Medtronic, Merck, Novartis, Roche, Sanofi-Genzyme, and Teva.The institution of B Willekens has received honoraria for acting as a member of Scientific Advisory Boards for Almirall, Biogen, Celgene/BMS, Merck Serono, Novartis, Roche, Sanofi-Genzyme and speaker honoraria and travel support from Biogen, Merck Serono, Novartis, Roche, Sanofi-Genzyme, TEVA; research and patient support grants from Roche, Biogen, Merck-Serono, Novartis, Sanofi-Genzyme.Valerie Delvaux, Miguel D’haeseleer, Daniel Guillaume, Guy Laureys, Guy Nagels, Patrick Vanderdonckt and Vincent Van Pesch have not conflict of interest related to this manuscript.