Abstract
The early stages of COPD have recently become a hot topic as many new risk factors have been proposed, but substantial knowledge gaps remain in explaining the natural history of the disease. If we are to modify the outcomes of COPD, early detection needs to play a critical role. However, we need to sort out the barriers to early detection and have a better understanding of the definition of COPD and its diagnosis and therapeutic strategies to identify and treat patients with COPD before structural changes progress. In this review, we aim to clarify the differences between early COPD, mild COPD and early detection of COPD, with an emphasis on the clinical burden and how different outcomes (quality of life, exacerbation, cost and mortality) are modified depending on which definition is used. We will summarise the evidence for the new multidimensional diagnostic approaches to detecting early pathophysiologic changes that potentially allow for future studies on COPD management strategies to halt or prevent disease development.