Table 2. Multivariate Cox regression analysis of clinical characteristics affecting the median PFS in stage IV NSCLC patients with EGFR-TKIs therapy.

Affecting factors	β	SE	Wald	Sig.	Exp (B)	95% CI	Sig.
Timing of targeted therapy	0.591	0.308	3.668	0.055	1.805	0.986–3.304	0.04
ECOG score	0.936	0.253	13.722	0	2.549	1.554–4.182	0