Inclusion Criteria:  Male or female patients, aged ≥40 years. Smokers or ex-smokers (≥10 pack-year). Prior hospitalization because of progressively worsening dyspnea (associated or not with increased cough and sputum, and or sputum purulence), with a clinically suspected diagnosis of exacerbations of COPD that prompt the discharging physician to refer the patient to the COPD Center. Signed informed concent form.  Exclusion Criteria:  Presenting to the hospital for similar symptoms, which are not defined by the clinicians as suspected exacerbations of COPD, because of alternative diagnoses not related to patients with COPD (e.g., chest wall trauma, neurological disorders, sepsis, cancer and anemia). Already enrolled in other studies perceived to interfere with this protocol. In whom spirometry test is contraindicated (e.g., hemoptysis, detached retina, active tuberculosis). Unable to comply with study procedures and follow-ups in the opinion of the Investigator (e.g., other severe diseases with short life expectancy or who make it impossible for the patients to participate into the study, evidence of alcohol or drug abuse, dementia, severe psychiatric disorder). Acute myocardial infarction and unstable angina pectoris or arrhythmias requiring specific cardiology ICU. Diagnosed stroke, dementia, degenerative neurological disorders or psychiatry disorders requiring specialized care. At the discretion of the recruiting clinician would not be able to be considered for the study.