Table 8– Prognostic factors for the overall survival from the initial diagnosis of idiopathic pulmonary fibrosis

Parameters	HR (95% CI)	p-value
Univariate Cox analysis
Age	1.016 (1.001–1.031)	0.032
Male sex	0.910 (0.685–1.209)	NS
Smoking	0.737 (0.568–0.956)	0.021
PFT % pred
FVC	0.976 (0.968–0.984)	<0.001
D_L,CO	0.978 (0.971–0.986)	<0.001
TLC	0.975 (0.965–0.984)	<0.001
BAL
Macrophages	1.003 (0.993–1.014)	NS
Lymphocytes	0.998 (0.985–1.012)	NS
Neutrophils	0.996 (0.980–1.012)	NS
Eosinophils	0.979 (0.941–1.018)	NS
CRP	1.073 (0.808–1.423)	NS
Steroid with/without cytotoxic agent	1.529 (1.177–1.986)	0.001
Occurrence of AE^#	2.770 (2.132–3.599)	<0.001
Multivariate Cox analysis^¶
Age	1.017 (1.001–1.033)	0.032
PFT % pred
FVC	0.987 (0.977–0.997)	0.009
D_L,CO	0.985 (0.976–0.994)	0.001
Steroid with/without cytotoxic agent	1.552 (1.113–2.164)	0.010
Occurrence of AE	2.592 (1.888–3.560)	<0.001

HR: hazard ratio; PFT: pulmonary function test; % pred: % predicted; FVC: forced vital capacity; D_L,CO: carbon monoxide diffusing capacity of the lung; TLC: total lung capacity; BAL: bronchoalveolar lavage; CRP: C-reactive protein; AE: acute exacerbation; NS: not significant. ^#: overall occurrence during follow up; ^¶: TLC % pred was excluded from the multivariate analysis due to the close correlation between FVC and TLC % pred (r = 0.765; p<0.001).