Table 2 Multivariate cox regression analysis indicating significant risk factors for progression-free survival in patients treated with combination chemotherapy and immunotherapy

CRP (Elevated vs. Normal)

1.84

1.13–3.00

0.014

1.89

1.06–3.36

0.031

Age (≥65 vs. < 65 years)

0.97

0.61–1.54

0.891

Sex (Male vs. Female)

1.15

0.46–2.88

0.761

Smoke (Current/Former vs. Never)

1.28

0.51–3.19

0.596

ECOG score (1 vs. 0)

1.09

0.54–2.19

0.816

LDH (Elevated vs. Normal)

1.73

1.06–2.82

0.029

1.44

0.80–2.58

0.225

NLR (≥3 vs. < 3)

1.19

0.72–1.96

0.500

PD–L1 (1–49 vs. < 1%)

0.59

0.24–1.43

0.240

PD–L1 (≥50 vs. < 1%)

0.65

0.30–1.42

0.281

Brain metastases (Presence vs. Absence)

2.10

1.00–4.43

0.049

1.66

0.66–4.20

0.283

Liver metastases (Presence vs. Absence)

1.14

0.63–2.05

0.660

Bone metastases (Presence vs. Absence)

1.74

1.08–2.8

0.023

1.79

1.07–3.00

0.026