Pulmonary Disease, Chronic Obstructive

• Bispebjerg og Frederiksberg Hospital — København NV, Denmark
• Odense University Hospital — Odense C, Denmark
• PAREXEL International GmbH — Berlin, Germany
• IKF Pneumologie GmbH & Co. KG — Frankfurt, Germany

Not specified

Not specified

• The First Affiliated Hospital of Guangzhou Medical University — Guangzhou, Guangdong, China

• The First Affiliated Hospital of Guangzhou Medical University — Guangzhou, Guangdong, China

• Research site — Beijing, China

• Research Site — Edegem, Belgium
• Research Site — Erpent, Belgium

• Centre for Clinical Epidemiology, McGill University — Montreal, Canada

• University Hospital Basel — Basel, Switzerland

• Beaumont Hospital — Beaumont, Dublin, Ireland