Additional Study Information: We are asking you to participate in a research study to determine if we can detect changes in enzymes in the blood that may influence lung function decline in COPD (chronic obstructive pulmonary disease), in particular after COPD exacerbations. The procedures of the study include a pulmonary function test (breathing test), a short questionnaire, and blood and urine samples. The duration of the study is two years: first visit, followed by a second visit two years later. If you were to experience a COPD exacerbation (increased cough, sputum, shortness of breath requiring oral or IV steroids and/or antibiotics), we ask that you contact us for repeat blood draws and urine sample within three days of illness and again 30 days later. In addition, if not done in the clinical setting, a nasal swab will be performed to test for viral respiratory infections. For each completed visit (first visit, second visit two years later, and any intermediate visits), we will compensate $100 allocated in a Visa gift card. For more detailed information please contact Laura, Clinical Research Coordinator.