ECOS is a cross-sectional, observational, longitudinal, multicenter study enrolling 100-200 patients during a COPD exacerbation.

Patients will be followed for 12 months. Information to be collected includes clinical, analytical, immunological, microbiological, hemodynamic, imaging, environmental, social and other blood markers of inflammation (IL-8, IL-6, TNF, TNF-alpha, endothelin-1, SLPI, IL10, TGF-beta and markers oxidative stress (TEAC)), and sputum (cell count, IL-6, IL-8, SLPI, ET 1, IL10).

Each center will collect clinical data, blood gas, microbiological and functional data for their patients, which will be centralized through the website of the Red Respira (www.redrespira.net).

A frozen serum sample and another of frozen sputum supernatant will be sent to the coordinating center (Palma de Mallorca).

Statistical analysis will include descriptive statistics: mean, standard deviation and range. Comparison of quantitative variables to be assessed using Student's t-test and ANOVA. Correlations between variables will be performed using bivariate analyzes (Pearson's linear correlation coefficient) and multivariate (multiple regression) analyses, among others.

Inclusion Criteria:

• Men and women
• Ages 40-80 years
• Diagnosis of COPD (according to ATS/ERS consensus guidelines)
• Smoking history ≥ 10 pack years
• Hospitalization for exacerbation of COPD

Exclusion Criteria:

• Pneumonia.
• Pneumothorax.
• Severe comorbidities, such as:
• -Advanced cancer.
• -Pulmonary tuberculosis, which affects more than one third of the total lung parenchyma.
• -Pneumonectomy.
• -Previous diagnosis of left heart failure.
• -Cardiomyopathy with ventricular dysfunction (ejection fraction <45%).
• -Chronic inflammatory diseases such as asthma, rheumatoid arthritis, pulmonary fibrosis and autoimmune diseases.
• Mechanical Ventilation.
• Existence of an exacerbation of COPD in the 4 weeks prior to admission.
• MRSA.
• History of thoracic/lung surgery in the past two years
• General weakness/malaise (difficulty in walking, lack of autonomy, etc.). that substantially hinders participation in the study, regardless of their willingness to participate.
• Mental incapacity according to the investigator judgment.
• Not resident in the province in which the hospital is located.
• Not fluent in Spanish
• Allergy to iodinated contrast
• Morbid obesity (BMI> 40)

COPD patients admitted in any of the participating ECOS hospitals with a diagnosis of COPD exacerbation