The review is devoted to topical issues of terminology, diagnostic criteria and principles of therapy for a pathological condition known as "Asthma-COPD overlap". Specialists in the field of pulmonology have got used to such term as "Astma- COPD overlap" (ACO), but till now the nuances of diagnostics and treatment of such patients are not developed. The prevalence of ACO in the population varies within 2–55 %. This discrepancy is due, first of all, to the absence of clearly defined criteria of

more »

... he ACO. Nowadays, the prevailing view is that the ACO is a state characterized by persistent air flow limitation with several signs usually associated with asthma or COPD. This is not a definition of a single disease, but a description term for clinical use, which includes several different clinical phenotypes. The risk of ACO is that the patients have frequent exacerbations, higher mortality, fast lung function decline and worse quality of life. For the purpose of diagnosis of ACO, it is recommended to use the large criteria (persistent airflow limitation (post-bronchodilation FEV1/FVC < 0.7 or the lower limit of normal) in patients aged 40 years and older, with at least 10 pack-years of tobacco smoking or equivalent exposure to indoor or outdoor air pollution, documented history of asthma under 40 years or post-bronchodilation Δ FEV1 > 400 ml) and small criteria (documented history of atopy or allergic rhinitis, post-bronchodilation ΔFEV1 > 200 ml and 12% of baseline values during 2 or more visits, the number of eosinophils in the peripheral blood ≥ 300 cells per μl). Patients with ACO should use therapy containing inhaled corticosteroids (ICS), as this reduces the risk of their hospitalization and death compared to long-term treatment only with bronchodilators. Availability of ACO requires review of planned therapy for patients who previously had asthma or COPD diagnosis only. If COPD is accompanied by asthma, patients should be prescribed ICS as soon as possible. When asthma is accompanied by COPD and at the same time the patient is already taking ICS and long-acting beta-agonists, then long-acting M-cholinolytics should also be considered. Research in the field of the diagnosis and treatment of ACO continues, as some questions are still to be answered. Key words: asthma, chronic obstructive pulmonary disease, asthmaCOPD overlap, diagnosis, treatment.