Table 4.

Multivariate Cox-proportional hazards analysis for predicting AE-IPF.

Variables	HR	95%CI	p Value
Age (continuous)	0.97	0.91–1.03	0.29
Male sex	0.59	0.18–1.89	0.37
Japanese Ethnicity	4.59	1.50–13.98	0.0074
%VC > 74% (median)	0.55	0.21–1.43	0.22
GGO > 4.5%	2.81	1.13–6.96	0.026
Fibrosis area > 18.7%	2.68	1.06–6.76	0.037

AE-IPF, acute exacerbation of idiopathic pulmonary fibrosis: HR, hazard ratio: VC, forced vital capacity: GGO, ground glass opacity: CI, confidence interval.