Table 3. Effect of altered thymic density and prognostic factors on overall survival after immune checkpoint inhibitor therapy in univariate and multivariate Cox regression models (n=412).

Parameter	Univariate analysis			Multivariate analysis
	Hazard ratio (95% CI)	P		Hazard ratio (95% CI)	P
Gender
Male	Reference
Female	0.84 (0.45, 1.56)	0.57
Age (years)
<65	Reference			Reference
≥65	1.91 (1.30, 2.80)	<0.001		1.80 (1.21, 2.67)	0.004
Body mass index (kg/m2)
< median*	Reference
≥ median	0.76 (0.45, 1.30)	0.32
Total bilirubin (mg/dL)	1.02 (0.99, 1.06)	0.25
A/G ratio	0.58 (0.31, 1.09)	0.09		0.64 (0.33, 1.24)	0.19
Smoking
No	Reference
Yes	1.08 (0.74, 1.59)	0.68
Hypertension
No	Reference			Reference
Yes	1.68 (1.14, 2.47)	0.01		1.37 (0.91, 2.05)	0.13
Hyperlipidemia
No	Reference
Yes	0.97 (0.64, 1.46)	0.87
Neutrophil to lymphocyte ratio
≤2	Reference
>2	1.52 (0.85, 2.72)	0.16
Platelet to lymphocyte ratio
≤150	Reference			Reference
>150	1.61 (1.05, 2.47)	0.03		1.30 (0.83, 2.03)	0.25
Pathological types
Adenocarcinoma	Reference
Squamous carcinoma	0.80 (0.54, 1.18)	0.26
Other	0.70 (0.28, 1.75)	0.45
Stages
Stage III	Reference			Reference
Stage IV	2.26 (1.34, 3.79)	0.002		2.23 (1.31, 3.79)	0.003
Type of ICIs
PD-1 antibody	Reference
PD-L1 antibody	1.03 (0.52, 2.04)	0.94
Group
Loss	Reference			Reference
Non-loss	1.79 (1.21, 2.65)	0.004		1.68 (1.13, 2.50)	0.010

*, the median body mass index is 25 kg/m². Non-loss, patients with no loss of thymic density; Loss, patients with loss of thymic density; CI, confidence interval; A/G ratio, ratio of albumin to globulin; ICIs, immune checkpoint inhibitors; PD-1, programmed cell death-1; PD-L1, programmed cell death-ligand 1.