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

Abstract

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity worldwide, with high and growing prevalence. Its underdiagnosis and hence under-treatment 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.

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Keywords:

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

View correction statement:

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

Supplementary materials

In Slovenia, the National Institute of Public Health (NIJZ) is a state institution that reports on the prevalence of diseases at a national level. In Tables S1–S3, the data from year 2008 are presented in a small region of northern Slovenia (with prevalence of smoking, above average Slovenian level). The striking finding is the high prevalence of smoking in younger adults, which is increasing mostly in young women. The overall prevalence of COPD in that region is 5.7% and in smokers 16.6%.

Table S4 describes the trend of self-reported diagnosis of either asthma or chronic bronchitis (including COPD) in 2014 compared to 2007 in Slovenia. All answers of yes were supplemented by a doctor’s confirmation of diagnosis. Ten-year groups were created in the report of prevalence. The decrease in prevalence of both conditions is seen in the 7-year period.

Table S1 Smoking exposure and COPD prevalence from the year 2008

Table S2 Hospital admissions in the year 2007

Table S3 Hospitalization costs in the year 2007

Table S4 Prevalence of the disease

References

• BožičAZupaničTHealth and Health Care in SloveniaStatistical Office of the Republic of Slovenia2009 Available from:http://www.nijz.si/sites/www.nijz.si/files/publikacije-datoteke/health_and_healthcare_in_slovenia_0.pdfAccessed June 7, 2017
   Google Scholar
• Ljubljana: Institute of Public Health of the Republic of Slovenia, 2010Hlastan RibicCDjombaJKZaletel-KrageljLTvegana vedenja, povezana z zdravjem in nekatera zdravstvena stanja pri odraslih prebivalcih Slovenije: Rezultati raziskave Dejavniki tveganja za nenalezljive bolezni pri odraslih prebivalcih Slovenije 2008 – Z zdravjem povezan vedenjski slog Available from:https://www.dlib.si/details/URN:NBN:SI:doc-9WUT23TJAccessed May 22, 2017
   Google Scholar
• SlačekSPrevalenca obstruktivnega sindroma v PomurjuKošnikMObravnava bolnika na intenzivnem. Unit: 5. Golniški symposiumGolnik, Brdo9th–14th October 2006Golnik Hospital, Clinic of Respiratory and Allergic Diseases2006127128
   Google Scholar

Acknowledgments

The authors acknowledge the scientific contribution of the following European Pulmonology Societies: AIPO – Italian Association of Hospital Pulmonologists, Croatian Pulmonology Society, Croatian Thoracic Society, HTS – Hellenic Thoracic Society, SEPAR – Spanish Society of Pneumology and Thoracic Surgery, Slovenian Respiratory Society. The authors would like to thank the staff of AIPO Ricerche (Milan, Italy) for editing assistance. This consensus document has been funded through an unrestricted educational grant from Teva.

Disclosure

The authors report no conflicts of interest in this work.