Table 3 Cox proportional hazard analysis of the prognostic factors for progression-free survival and overall survival

Age, years

0.103

0.225

 < 65

1

1

 ≥ 65

0.723

0.489–1.068

0.788

0.536–1.158

Sex

0.009

0.047

 Female

1

1

 Male

1.796

1.161–2.779

1.550

1.006–2.380

BMI, kg/m²

0.021

0.030

 < 25

1

1

 ≥ 25

0.550

0.330–0.915

0.576

0.350–0.949

ECOG PS

0.047

0.051

0.017

0.013

 0

1

1

1

1

 ≥ 1

2.325

1.013–5.338

2.319

0.996–5.400

2.766

1.197–6.390

2.934

1.253–6.867

Smoking status

0.027

0.011

0.069

0.021

 Never smoker

1

1

1

1

 Ever-smoker

0.626

0.414–0.949

0.567

0.367–0.877

0.674

0.446–1.018

0.603

0.392–0.926

Histologic type

0.178

0.022

0.112

0.013

 Squamous cell carcinoma

1

1

1

1

 Non-squamous cell carcinoma

0.755

0.501–1.137

0.588

0.373–0.925

0.738

0.492–1.108

0.568

0.363–0.890

PD-L1 expression

0.855

0.478

 Negative

1

1

 Positive

1.048

0.635–1.727

0.835

0.507–1.374

Type of ICI

0.054

0.025

 Anti-PD-1 or anti-PD-L1 monotherapy

1

1

 ICI-based combination therapy

0.613

0.372–1.009

0.566

0.344–0.930

No. of lines of prior systemic therapy

0.001

0.001

0.001

0.002

 0

1

1

1

1

 ≥ 1

2.388

1.416–4.028

2.368

1.396–4.018

2.275

1.367–3.788

2.266

1.357–3.785

Skeletal muscle index

0.520

0.894

 Q1

1

1

 Q2-4

1.160

0.738–1.821

0.970

0.619–1.520

Total fat index

0.622

0.642

 Q1

1

1

 Q2–4

0.895

0.577–1.390

0.901

0.581–1.397

Visceral fat index

0.007

0.004

0.005

0.002

 Q1

1

1

1

1

 Q2–4

0.554

0.360–0.853

0.497

0.307–0.804

0.542

0.353–0.834

0.466

0.290–0.748

Subcutaneous fat index

0.851

0.996

 Q1

1

1

 Q2–4

0.959

0.618–1.488

0.999

0.645–1.548