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

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


Background and objective: 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).

Methods: 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.

Results: 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.

Conclusions: 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.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Bronchiectasis / epidemiology
  • Cognition Disorders / epidemiology
  • Cohort Studies
  • Comorbidity
  • Female
  • Forced Expiratory Volume
  • Humans
  • Lung Diseases / epidemiology
  • Male
  • Middle Aged
  • Oxygen Inhalation Therapy
  • Patient Selection*
  • Pragmatic Clinical Trials as Topic / standards*
  • Pulmonary Disease, Chronic Obstructive / epidemiology
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Pulmonary Disease, Chronic Obstructive / therapy
  • Randomized Controlled Trials as Topic / standards*
  • Retrospective Studies
  • Smoking / epidemiology