Article History
Received: 13 December 2017
Revised: 13 April 2018
Accepted: 1 May 2018
First Online: 21 May 2018
Competing interests
: M.L. has accepted fees for lectures and advisory boards from Chiesi, Napp, Soar Beyond, Boehringer Ingelheim, AzstraZeneca and Teva Pharmaceuticals. The remaining authors declare no competing interests.