Pre–Chronic Obstructive Pulmonary Disease: Toward the Limits of the Spirometric Funnel

To the Editor:

In the February issue of the Journal, Han and colleagues (1) introduced the term “pre-COPD” to refer to individuals in whom spirometry is unable to detect airflow obstruction but who are at risk of subsequently developing chronic obstructive pulmonary disease (COPD) with a reduced FEV₁/FVC ratio. The authors adopt the concept of predisease status as in prediabetes or preeclampsia. The latter condition is not a predisease model but a serious complication during pregnancy, which is characterized by sharp rise in blood pressure, albuminuria, and edema. Recent data also suggest that prediabetes is not a robust diagnostic entity, at least not in older age (2). After the suggestion of the authors that chronic cough and phlegm stand apart as so-called nonobstructive chronic bronchitis, the authors refer to physiological variables (low to normal FEV₁, Dl_CO and/or accelerated FEV₁ decline) and/or radiographic abnormalities as emphysema or airway abnormalities. Considering that alveolar abnormalities are part of the definition of COPD, at least the presence of emphysema (assessed by imaging or using surrogate markers as Dl_CO) fulfills the criterion of structural disorder as formulated by the GOLD initiative, as well as by Criner and colleagues and Scadding and colleagues (3–5). Interestingly, the recently reported COPD Gene data illustrate that imaging in combination with symptoms and/or spirometry was predictive for COPD progression (6). Considering the wide availability of computed tomography, we urgently need to delineate the subtype of emphysema, referring to the original conclusions of the CIBA symposium dealing with the definitions and classification of chronic pulmonary emphysema and related conditions (7). As for other so-called predisease conditions, it must be realized that a new clinical category of pre-COPD will engender costs and disutilities related to self-image. The main driver for transformation could only be scientific evidence. A clear operational definition of pre-COPD and validation of cutoff points are needed to assess whether the problems of such a new label outweigh the benefits. The authors focus in particular on the development of airflow limitation using FEV₁/FVC ratio cutoff values. Based on new insights of lung function trajectories and the impact of dysanapsis on the variation of FEV₁/FVC ratio, it can be questioned whether the current physiological cutoff of airflow limitation is a marker of a disease condition, particularly in the absence of accelerated decline in FEV₁ (8, 9). Before introducing a new label as a window of opportunity for early intervention and prevention, nosology of chronic respiratory diseases must dynamically integrate the new scientific discoveries offered by new physiological and imaging facilities for correct identification of abnormalities. Therefore, it will become important to engage the scientific community regarding the development of a new taxonomy for these chronic respiratory disease conditions instead of the current concept of pre-COPD.