Table 4.

Cox’s regression analysis for PFS and OS

Factor	PFS						OS
	Univariate			Multivariate			Univariate			Multivariate
	HR	95% CI	p	HR	95% CI	p	HR	95% CI	p	HR	95% CI	p
Limited-stage
Age
< 70 years	Ref.						Ref.
≥ 70 years	1.147	0.742–1.774	0.537				1.343	0.848–2.125	0.208
ECOG PS
0–1	Ref.			Ref.			Ref.			Ref.
2–3	1.821	1.047–3.167	0.034	1.329	0.730–2.421	0.352	2.108	1.192–3.730	0.010	1.579	0.855–2.915	0.144
Smoking
Never-smoker	Ref.						Ref.
Current/former smoker	1.697	0.235–12.279	0.600				1.587	0.219–11.506	0.648
Regimen
Etoposide and platinum	Ref.			Ref.			Ref.			Ref.
Irinotecan and cisplatin	8.175	1.063–62.881	0.044	4.553	0.567–36.536	0.154	12.525	1.566–100.158	0.017	7.415	0.887–61.945	0.064
BMI
Other (≥ 18.5 kg/m2)	Ref.						Ref.
Underweight (<  18.5 kg/m2)	1.328	0.639–2.762	0.447				1.121	0.514–2.444	0.774
CXI
High	Ref.			Ref.			Ref.			Ref.
Low	2.768	1.671–4.587	<  0.001	2.445	1.406–4.253	0.002	2.830	1.698–4.717	<  0.001	2.393	1.372–4.174	0.002
Extensive-stage
Age
< 70 years	Ref.						Ref.
≥ 70 years	1.088	0.786–1.506	0.612				1.297	0.906–1.855	0.155
ECOG PS
0–1	Ref.			Ref.			Ref.			Ref.
2–3	2.083	1.435–3.023	<  0.001	1.819	1.236–2.679	0.002	3.152	2.121–4.684	<  0.001	2.768	1.847–4.149	<  0.001
Smoking
Never-smoker	Ref.						Ref.
Current/former smoker	1.071	0.264–4.344	0.924				0.989	0.244–4.016	0.988
Regimen
Etoposide and platinum	Ref.						Ref.
Irinotecan and cisplatin	0.819	0.471–1.426	0.481				0.779	0.434–1.396	0.401
BMI
Other (≥ 18.5 kg/m2)	Ref.						Ref.
Underweight (<  18.5 kg/m2)	1.243	0.775–1.994	0.367				1.052	0.631–1.754	0.847
CXI
High	Ref.			Ref.			Ref.			Ref.
Low	2.039	1.401–2.967	<  0.001	1.764	1.195–2.604	0.004	2.644	1.796–3.894	< 0.001	2.269	1.529–3.366	<  0.001

PFS progression-free survival, OS overall survival, HR hazard ratio, CI confidence interval, ECOG PS Eastern Cooperative Oncology Group performance status, BMI body mass index, CXI cachexia index