Table 1 Algorithm for the classification of chronic respiratory disease (based on the GOLD criteria21)
Lung functionRespiratory symptoms*Reversibility†Disease classification
No obstruction‡YesAsthmatic
No chronic symptomsNoNo COPD or asthma
Chronic symptomsNoAt risk for COPD (GOLD 0)
Obstruction‡YesInadequately managed asthma
    and FEV1§ ⩾80%NoMild COPD (GOLD I)
    or 50%⩽FEV1<80%NoModerate COPD (GOLD II)
    or 30%⩽FEV1<50%NoSevere COPD (GOLD III)

  • *Chronic symptoms: cough and sputum production for at least 3 months in each of two consecutive years.

  • †Reversibility: a 12% change in predicted FEV1 after bronchodilatation with a change of at least 200 ml.

  • ‡Obstructive if FEV1/vital capacity <70%.

  • §Post-bronchodilator forced expiratory volume.

  • COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; GOLD, Global Initiative for Chronic Obstructive Lung Disease.