Avoiding confusion in COPD: from risk factors to phenotypes to measures of disease characterisation: Table 1–

Because chronic obstructive pulmonary disease (COPD) is a complex disorder with different pulmonary and extrapulmonary manifestations [1], there is great interest in better understanding the complexity of COPD in order to facilitate a more accurate risk stratification of patients and a better understanding of disease pathobiology, and eventually develop more targeted therapy and improved management of patients with the disease. One end-product of the great number of studies addressing the complexity of COPD has been the emergence of several concepts and terms that are often used (and misused) in scientific discussions and publications (table 1). The purpose of this article is to contribute to the clarification of these concepts by summarising the meaning of the terms, so the scientific community can communicate and discuss advances in the field of COPD, being confident that there is no uncertainty or misunderstanding in their use. We accept this to be only a first proposal and that some investigators may disagree with its content. We invite them to correspond with us in the European Respiratory Journal such that, eventually, a consensus may emerge. View this table: Table 1– Terms and definitions A risk factor is “an aspect of personal behaviour or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiological evidence, is known to be associated with a health-related condition” [2]. Examples of well-established risk factors in COPD include age [9], smoking [10], …