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Respiration. 2014;87(1):11-7. doi: 10.1159/000355082. Epub 2013 Nov 20.

What proportion of chronic obstructive pulmonary disease outpatients is eligible for inclusion in randomized clinical trials?

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Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Pneumologia, University of Palermo, Palermo, Italy.



We aimed to explore to what extent an unselected population of chronic obstructive pulmonary disease (COPD) outpatients would be eligible for inclusion in randomized clinical trials (RCTs).


Retrospective analysis of the clinical records of outpatient subjects with an ascertained diagnosis of COPD. COPD outpatients were assessed against the following inclusion criteria: 40 < age < 80 years, current or former smokers, forced expiratory volume in the first second (FEV1) <70% predicted, no long-term oxygen therapy, no other concomitant lung diseases and absence of major extrapulmonary comorbidities. The study consisted of 2 phases; in phase 1, the criteria for inclusion in RCTs on COPD were selected, and in phase 2, the above criteria were applied to an unselected outpatient COPD population.


A total of 578 subjects (83% of the whole group) failed at least one of the inclusion criteria. Lung diseases other than COPD (occurring in 30% of our population, mostly bronchiectasis), long-term oxygen therapy (31%), FEV1 (19%), age (14%) and extrapulmonary comorbidities such as cognitive impairment (14%), arrhythmias (17%) and congestive heart disease (13%) would have been the most frequent causes for exclusion from RCTs.


In real-life settings, more than 80% of COPD subjects are currently treated by protocols based on results of RCTs for which they would not have been eligible. We encourage a more extensive use of pragmatic trials in COPD to better modulate the application of results of RCTs to patients encountered in daily practice.

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