Table 2. Results of univariate analyses using the Cox proportional hazards model.

Variable	Hazard ratio	Standard error	P value	95% CI
Univariate analyses
PD-L1 category
Negative	Reference
Low	1.12	0.29	0.68	[0.67; 1.87]
High	1.70	0.53	0.09	[0.92; 1.13]
Performance status
0 or 1	Reference
2 or above	1.96	0.54	0.02	[1.14; 3.36]
Comorbidity
None	Reference
Any	0.94	0.22	0.80	[0.59; 1.50]
EGFR mutation
Common	Reference
Uncommon	2.85	0.82	0.00	[1.63; 5.00]
Drug
Erlotinib	Reference
Osimertinib or both	0.51	0.12	0.01	[0.31; 0.82]
Metastatic stage (TNM)
0 or 1A	Reference
1B	2.03	0.56	0.01	[1.18; 3.48]
Brain metastases
No	Reference
Yes	1.71	0.51	0.07	[0.95; 3.01]
Multivariate analysis
PD-L1 category	1.29	0.22	0.13	[0.92; 1.79]
Performance status	2.04	0.59	0.01	[1.16; 3.58]
EGFR mutation	2.71	0.81	0.00	[1.50; 4.88]
Drug	0.47	0.12	0.00	[0.28; 0.79]
Metastatic stage (TNM)	1.68	0.50	0.08	[0.94; 3.01]

Independent variables with P values of 0.05 or less were included in the multivariate model. PD-L1, programmed death ligand-1; EGFR, epidermal growth factor receptor; TNM, Tumour, Node, Metastasis.