To quantify the relationship between severity of chronic obstructive pulmonary disease (COPD) as expressed by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage and the annual exacerbation frequency in patients with COPD.
Int J Chron Obstruct Pulmon Dis. 2010;5:435-44
Authors: Hoogendoorn M, Feenstra TL, Hoogenveen RT, Al M, Mölken MR
