Chronic obstructive pulmonary disease with mild airflow limitation: current knowledge and proposal for future research – a consensus document from six scientific societies

Abstract

Andrea Rossi,1 Bojana Butorac-Petanjek,2 Marco Chilosi,3 Borja G Cosío,4 Matjaz Flezar,5 Nikolaos Koulouris,6 José Marin,7 Neven Miculinic,2 Guido Polese,8 Miroslav Samaržija,9 Sabina Skrgat,5 Theodoros Vassilakopoulos,10 Andrea Vukić-Dugac,9 Spyridon Zakynthinos,10 Marc Miravitlles11 1Pulmonary Unit, University of Verona, Verona, Italy; 2Respiratory Department, University Hospital Centre, Zagreb, Croatia; 3Pathology Unit, University of Verona, Verona, Italy; 4Department of Respiratory Medicine, Hospital Son Espases-IdISPa and CIBERES, Palma, Spain; 5University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia; 6First Department of Respiratory Medicine, Medical School of National and Kapodistrian University of Athens, Greece; 7Respiratory Medicine, Hospital Universitario Miguel Servet, CIBERES & IISAragon, Zaragoza, Spain; 8Pulmonary Unit, ULSS 22 Bussolengo, Italy; 9Jordanovac Department for Respiratory Diseases, University of Zagreb School of Medicine, University Hospital Centre, Zagreb, Croatia; 10First Department of Critical Care and Pulmonary Services, Evangelismos Hospital, University of Athens, Greece; 11Pneumology Department, Hospital Universitary Vall d’Hebron, Barcelona, Spain Abstract: Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity worldwide, with high and growing prevalence. Its underdiagnosis and hence undertreatment is a general feature across all countries. This is particularly true for the mild or early stages of the disease, when symptoms do not yet interfere with daily living activities and both patients and doctors are likely to underestimate the presence of the disease. A diagnosis of COPD requires spirometry in subjects with a history of exposure to known risk factors and symptoms. Postbronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity <0.7 or less than the lower limit of normal confirms the presence of airflow limitation, the severity of which can be measured by FEV1% predicted: stage 1 defines COPD with mild airflow limitation, which means postbronchodilator FEV1 ≥80% predicted. In recent years, an elegant series of studies has shown that “exclusive reliance on spirometry, in patients with mild airflow limitation, may result in underestimation of clinically important physiologic impairment”. In fact, exercise tolerance, diffusing capacity, and gas exchange can be impaired in subjects at a mild stage of airflow limitation. Furthermore, growing evidence indicates that smokers without overt abnormal spirometry have respiratory symptoms and undergo therapy. This is an essential issue in COPD. In fact, on one hand, airflow limitation, even mild, can unduly limit the patient’s physical activity, with deleterious consequences on quality of life and even survival; on the other hand, particularly in younger subjects, mild airflow limitation might coincide with the early stage of the disease. Therefore, we thought that it was worthwhile to analyze further and discuss this stage of “mild COPD”. To this end, representatives of scientific societies from five European countries have met and developed this document to stimulate the attention of the scientific community on COPD with “mild” airflow limitation. The aim of this document is to highlight some key features of this important concept and help the practicing physician to understand better what is behind “mild” COPD. Future research should address two major issues: first, whether mild airflow limitation represents an early stage of COPD and what the mechanisms underlying the evolution to more severe stages of the disease are; and second, not far removed from the first, whether regular treatment should be considered for COPD patients with mild airflow limitation, either to prevent progression of the disease or to encourage and improve physical activity or both. Keywords: chronic obstructive pulmonary disease, COPD, airflow limitation, COPD staging, GOLD document, COPD pathophysiology

Keywords

• chronic obstructive pulmonary disease (COPD)
• airflow limitation
• COPD staging
• GOLD document
• COPD pathophysiology.