Table 3. Pulmonary function test according to airflow limitation severity*.

Variables	Airflow limitation† (N=56)
	Mild (n=11)	Moderate (n=15)	Severe (n=21)	Very severe (n=9)
FVC, L	3.03 [2.58–3.86]	2.99 [2.43–3.43]	2.10 [1.48–2.78]	1.61 [1.07–2.14]
FVC, % predicted	105 [95–115]	77 [74–89]	55 [48–74]	41 [32–59]
FEV1, L	1.92 [1.59–2.43]	1.49 [1.37–1.91]	1.00 [0.82–1.11]	0.60 [0.55–0.69]
FEV1, % predicted	94 [88–108]	64 [51–69]	42 [35–47]	24 [23–26]

The data are presented as median [interquartile change]. *, airflow limitation severity was defined was follows: (I) mild airflow limitation was defined as FEV₁/FVC <0.7 and FEV₁ ≥80% predicted; (II) moderate airflow limitation was defined as FEV₁/FVC <0.7 and 50% ≤ FEV₁ <80% predicted; (III) severe airflow limitation was defined as FEV₁/FVC <0.7 and 30%≤ FEV₁ <50% predicted; (IV) very severe airflow limitation was defined as FEV₁/FVC <0.7 and FEV₁ <30% predicted; ^†, “Airflow limitation” was defined using the FEV₁/FVC <0.7. FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second.