Table 3.

Subgroup analysis by chemotherapy regimen.

	Crude				Adjusted*
Variables	HR	95% CI		P value	HR	95% CI		P value
Chemotherapy regimen
Group 1 (mitomycin-based)
Used PSK (reference: nonuser)	0.72	0.62	0.83	<0.001	0.72	0.62	0.83	<0.001
Group 2 (epirubicin-based)
Used PSK (reference: nonuser)	1.22	0.86	1.72	0.268	1.24	0.87	1.77	0.234
Group 3 (platinum-based)
Used PSK (reference: nonuser)	0.75	0.63	0.90	0.002	0.74	0.62	0.90	0.002
Group 4 (others)
Used PSK (reference: nonuser)	0.77	0.68	0.87	<0.001	0.75	0.66	0.85	<0.001

^*Adjusted for age, sex, urbanization, income, and comorbidities.

CI = confidence interval, HR = hazard ratio, PSK = protein-bound polysaccharide K.