[Asthma-COPD-Overlap-Syndrome - when a diagnostic dilemma results in a new syndrome]

Symptomatic patients with airflow limitation need to have a diagnostic follow-up to distinguish chronic obstructive pulmonary disease (COPD) from asthma. In the majority of cases this can be easily done based on symptoms, exposition to e. g. allergens or cigarette smoke, measures of allergy, and extensive lung function testing. In a minority of patients, however, it is difficult to distinguish between asthma and COPD. The term "asthma-copd-overlap-syndrome" has been proposed fur such cases. The current problem with this proposal is the lack of studies that all used the same criteria to better characterize this syndrome. Furthermore, there is not a single therapeutic-interventional study that would allow a firm conclusion regarding the proposed therapy. Therefore, the primary diagnosis should still be either COPD or asthma.