The study is an observational multicenter descriptive study. It is planned to enroll approximately 1250 subjects with severe and very severe COPD hospitalized for the reason of COPD exacerbation into departments of pulmonology or therapy. The study will be conducted in approximately 20-25 institutions of treatment and prevention in Russian Federation and will include about 50 to 60 subject at each clinical site.

The study is an observational multicenter descriptive study. It is planned to enroll approximately 1000 subjects with severe and very severe COPD hospitalized for the reason of COPD exacerbation into departments of pulmonology or therapy. The study will be conducted in approximately 20-25 institutions of treatment and prevention in Russian Federation and will include about 50 to 60 subject at each clinical site.

This is an observational study, so there is no treatment protocol or subjects' management recommendations required. The study subjects receive medical treatment according to the routine practice for their disease in Russian Federation. A subject's participation in this clinical study should not affect character and amount of care provided according to the routine clinical practice.

The study includes 5 clinical visits: Study Enrolment Visit, Month 3 Visit, Month 6 visit, Month 9 Visit, Month 12 visit / End of Study Visit.

Inclusion Criteria:

• Signed informed consent . Men and women at least 40 years old, with smoking history more than 10 pack-years.
• Hospitalization for the reason of COPD exacerbation (exacerbation defined as acute condition, different from typical fluctuations of general condition and requiring change of therapy).
• Diagnosis of severe or very severe COPD based on final spirometry (performed in a standardized manner using salbutamol 400 mg), or history of diagnosis of severe or very severe COPD based on spirometry performed during 6 months before the hospitalization.

Exclusion Criteria:

• Participation in any interventional study.
• Concomitant respiratory diseases, i.e. confirmed or suspected malignancy or any other serious condition, including lung tumor, lung fibrosis, interstitial lung disease, tuberculosis, sarcoidosis.
• Patient is unable or unwilling to complete questionnaires, unable to understand study procedures, or other reasons which, in the investigator's opinion, could affect study procedures performance.

Patients of both genders aged 40 years and older, smokers, with smoking history more than 10 pack-years, with severe and very severe COPD who were hospitalized with COPD exacerbation