Study of Patient With Frequent Exacerbations in Moscow

This ambispective study consists of retrospective and prospective parts: * Retrospective part aims to describe the demographic and clinical characteristics, as well as therapeutic approaches in COPD outpatients with frequent exacerbations during the 52 weeks prior to screening; * Prospective part aims to evaluate current therapeutic approaches for such patients and their outcomes in real-world clinical practice. The patient participation in the study will include two visits: * Visit 1 - baseline: inclusion into the study, retrospective collection of medical history and data on COPD course and treatment during the previous 52 weeks, and primary data collection trough patient interview and physician assessment; * Visit 2 - follow-up at Week 24 (±6): primary data collection trough patient interview and physician assessment. All visits will be conducted by a study physician in accordance with routine clinical practice for the observation and management of COPD patients. For each eligible patient, the study physician will collect data in an individual electronic Case Report Form (eCRF) based on source medical documentation. Expected duration of the inclusion period is 12 months OR until 500 eligible patients are included into the study, whichever occurs first. Overall expected duration of the study (from the first patient inclusion to the last patient last visit) is approximately 25 months.