Definition and diagnostic criteria

COPD or chronic obstructive pulmonary disease is characterised by chronic airway obstruction resulting in airflow limitation that is not fully reversible.

COPD primarily affects people aged over 45. Its main characteristic is a progressive and irreversible decline of pulmonary function, usually associated with smoking, its main risk factor.

The ERS diagnostic criteria for COPD include the following symptoms: coughing, sputum production and/or dyspnoea, as well as a history of exposure to risk factors for COPD. The diagnosis is confirmed by a post-bronchodilator FEV1/FVC < 0.7 in spirometry, as sign of the airflow limitation that is not fully reversible.

According to the symptoms and the spyrometric parameters, the COPD has four stages, from mild (stage I) to very severe (stage IV).

ICD classification

The GOLD guide to COPD emphasizes the distinction between chronic bronchitis, emphysema and asthma. As a diagnostic category, the term "chronic airways obstruction" was first established in 1979 with the introduction of ICD-9, replacing 'chronic bronchitis and emphysema'.

The current, ICD-10 classification classifies COPD under "Chronic lower respiratory diseases" (J40-J47). Apart from the group 'Other chronic obstructive pulmonary disease' (J44), several other groups are included, such as: 'Bronchitis, not specified as acute or chronic' (J40), 'Simple and mucopurulent chronic bronchitis' (J41), 'Unspecified chronic bronchitis' (J42), 'Emphysema' (J43), 'Asthma' (J45), 'Status asthmaticus' (J46), and 'Bronchiectasis' (J47). This classification came into use in WHO Member States as from 1994.

The presumed underestimation of COPD prevalence and mortality, reflects the variations and changes in terminology, diagnostic criteria and ICD coding (European Lung White Book, 2003).