Table 1.

Comparison of the baseline characteristics in patients with IPF according to the HRCT patterns

	UIP	Probable	Indeterminate	Alternative	P-value
No. of patients	163	110	33	31
Age, years	61.9 ± 7.6	62.9 ± 7.3	63.0 ± 7.7	63.5 ± 7.8	0.550
Male	133 (81.6)	71 (64.5)†	29 (87.9)	17 (54.8)†	< 0.001
Ever-smokers	126 (77.3)	66 (60.0) †	28 (84.8)	12 (38.7) †	0.001
PFT, % predicted (n = 336)	n = 163	n = 110	n = 33	n = 30
FVC	69.9 ± 18.5†	73.7 ± 14.9†	84.6 ± 13.6	66.7 ± 18.5†	< 0.001
DLCO	57.6 ± 17.2†	66.5 ± 17.0	70.2 ± 21.1	58.4 ± 13.5†	< 0.001
TLC	69.7 ± 15.1†	73.1 ± 13.3†	83.5 ± 11.4	69.3 ± 15.3†	< 0.001
6MWT (n = 324)	n = 157	n = 107	n = 32	n = 28
Distance, meter	448.2 ± 110.7	459.5 ± 95.4	475.3 ± 92.2	440.6 ± 110.5	0.461
Initial SpO2, %	96.0 ± 1.8†	96.5 ± 1.3†	97.3 ± 1.1	96.3 ± 1.7†	< 0.001
Lowest SpO2, %	89.5 ± 6.0†	92.2 ± 4.5	93.5 ± 5.0	89.7 ± 6.2†	< 0.001
BAL fluid analysis (n = 220)	n = 118	n = 72	n = 15	n = 15
WBC, /μl	289.2 ± 278.4	305.0 ± 237.2	354.7 ± 305.5	233.5 ± 171.0	0.622
Neutrophil, %	12.0 ± 20.2	8.6 ± 15.3	6.5 ± 5.5	12.9 ± 18.8	0.438
Lymphocyte, %	13.2 ± 12.6	12.0 ± 10.4	15.9 ± 15.9	15.7 ± 13.9	0.570
Treatment
Antifibrotic agents	56 (34.6)	46 (42.2)	12 (36.4)	5 (16.7)	0.258
Steroid ± IM	63 (38.9)	38 (34.9)	8 (24.2)	16 (53.3)	0.737
No treatment	43 (26.5)	25 (22.9)	13 (39.4)	9 (30.0)	0.392

Data are expressed as a mean ± standard deviation or a number (%) unless otherwise indicated

IPF, idiopathic pulmonary fibrosis; HRCT, high-resolution computed tomography; UIP, usual interstitial pneumonia; PFT, pulmonary function test; FVC, forced vital capacity; DL_CO, diffusing capacity of the lung for carbon monoxide; TLC, total lung capacity; 6MWT, six-minute walk test; SpO₂, saturation of peripheral oxygen; BAL, bronchoalveolar lavage; WBC, white blood cell; IM, immunosuppressant

^†There was a statistically significant difference compared to indeterminate for UIP (P < 0.05)