Background: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory condition, and progresses with acute exacerbations. (AE). During AE, levels of acute phase reactants such as C-reactive protein (CRP) and inflammatory cells in the circulation increase. Soluble urokinase-type plasminogen activator receptor (suPAR) levels increase in acute viral and bacterial infections and in diseases involving chronic inflammation. The purpose of this study was to investigate the effectiveness of suPAR in predicting diagnosis of AE of COPD (AE-COPD) and response to treatment.