Box 1.
Numbers of COPD Patients in the Four Severity Stages According to the Five Classifications of AFL.
| “Light” |
“Severe” |
|||
|---|---|---|---|---|
| Severity of the AFL | Mild | Moderate | Severe | Very severe |
| AFL classifications (reference) | ||||
| FEV1%pred GOLD. (2019) | ≥80% (n = 2) |
50% to 80% (n = 18) |
30% to 50% (n = 23) |
<30% (n = 12) |
| FEV1z-score Quanjer et al. (2014) | ≥ −2 (n = 3) |
−2 to −3 (n = 3) |
−3 to −4 (n = 8) |
< −4 (n = 41) |
| FEV1/height2 Miller et al. (2007) | ≥0.5 (n = 31) |
0.4 to 0.5 (n = 10) |
0.3 to 0.4 (n = 7) |
<0.3 (n = 7) |
| FEV1/height3 Miller and Pedersen (2010) | ≥0.38 (n = 18) |
0.29 to 0.38 (n = 14) |
0.22 to 0.29 (n = 11) |
<0.22 (n = 12) |
| FEV1Quotient Miller and Pedersen (2010) | ≥3.38 (n = 19) |
2.50 to 3.38 (n = 14) |
1.90 to 2.50 (n = 12) |
<1.90 (n = 10) |
Note. AFL = airflow limitation; COPD = chronic obstructive pulmonary disease; FEV1 = post-bronchodilator forced expiratory volume in 1 s; n = number; %pred = % of the predicted value.