The study aims to evaluate the degree to which data from large clinical trials can be applied to treat COPD outpatients at a local hospital. The authors used a real-world cohort of 303 consecutively included COPD outpatients from a previous cross-sectional study to apply their inclusion and exclusion criteria to seventeen RCTs systematically selected from the GOLD 2019 consensus document.

Only a small percentage of the real-world cohort of COPD outpatients—ranging from 4.29% to 60.07%—were qualified to participate in the referred trials when the inclusion criteria of the 17 RCTs were applied to them. However, only 3.63% to 40.59% of patients were qualified to participate after using both the inclusion and exclusion criteria. As a result, only a small fraction of the patients in this cohort may profit from the results of these RCTs.

There is a need to augment the efficacy proof provided by large RCTs by determining how far their results, which were designed to target specific patient populations, can be applied to typical patients treated in daily clinical practice.