Table 2. Univariate and multivariate Cox proportional hazard regression analysis to evaluated prognostic factors.

Parameters	HR	95% CI	P value
Univariate analysis
Gender, male vs. female	0.987	0.403–2.416	0.978
Age	1.027	0.980–1.076	0.272
Smoking, CS or ES vs. NS	0.877	0.336–2.289	0.789
Diagnosis of IPF, Clinical vs. SLB	1.696	0.831–3.460	0.147
BMI	0.939	0.839–1.051	0.277
mMRC, ≥2 vs. <2	4.591	2.247–9.380	<0.001
%FVC*	0.950	0.930–0.971	<0.001
%DLco**	0.960	0.939–0.983	0.001
Neutrophils in BAL*, %	1.087	1.011–1.169	0.025
Lymphocytes in BAL*, %	0.973	0.919–1.029	0.338
KL-6*, ×100 U/mL	1.056	1.018–1.095	0.004
SP-D*, ×10 ng/mL	1.020	1.005–1.036	0.009
Multivariate analysis stepwise selection procedure
%FVC	0.955	0.930–0.982	0.001
mMRC, ≥2 vs. <2	2.824	1.265–6.305	0.011
Lymphocytes in BAL, %	0.927	0.866–0.991	0.027

Prognostic significance of each parameter was evaluated by univariate Cox proportional hazard regression analysis. Multivariate analysis with stepwise method was performed using all parameters to clarify prognostic factors. *, n=68; **, n=67, n=69 for the other parameters. HR, hazard ratio; CI, confidence interval; IPF, idiopathic pulmonary fibrosis; BMI, body mass index; mMRC, modified Medical Research Council score for shortness of breathe; %FVC, percent predicted value of forced vital capacity; %DLco, percent predicted value of diffusing capacity of carbon monoxide; KL-6, Krebs von den Lungen-6; SP-D, surfactant protein.