DISCLOSURES: Maher has received grants, consulting fees, and speaker fees from GlaxoSmithKline and UCB and grants from Novartis. He has also received consulting fees and speaker fees from AstraZeneca, Bayer, Biogen Idec, Boehringer Ingelheim, Cipla, Lanthio, InterMune International AG (a wholly owned Roche subsidiary since 2014), F. Hoffmann-La Roche, Sanofi-Aventis, and Takeda. Maher is supported by a National Institute for Health Research Clinician Scientist Fellowship (NIHR Ref: CS:-2013-13-017). Dejonckheere is an employee of F. Hoffmann-La Roche. Nathan has received consulting fees from Roche-Genentech and Boehringer Ingelheim. He is also on the speakers bureau for Roche-Genentech and Boehringer Ingelheim and has received research funding from both companies. All authors contributed equally to study concept and design, data collection and analysis, and manuscript preparation.