Table 3.

Multivariable analysis in Group A including SIRI^a as independent variable for predicting overall survival

Variable	Univariable analysis			Multivariable analysis
	HRb	95% CIc	P value	HR	95% CI	P value
Age			< 0.001			< 0.001
≤ 60 years	1			1
> 60 years	2.017	1.688–2.410		1.904	1.569–2.311
Sex			0.490
Female	1
Male	0.943	0.800–1.113
Tobacco use			0.004			0.841
Never	1			1
Ever	1.297	1.089–1.545		1.020	0.841–1.237
Alcohol use			0.269
Never	1
Ever	0.906	0.759–1.080
WUHNCId			< 0.001			0.078
0	1			1
≥ 1	1.614	1.359–1.917		1.187	0.981–1.436
Vascular invasion			< 0.001			0.080
Absent	1			1
Present	2.119	1.713–2.621		1.242	0.975–1.583
Perineural invasion			< 0.001			0.013
Absent	1			1
Present	2.143	1.806–2.543		1.310	1.060–1.620
Margin status			< 0.001			0.001
Negative	1			1
Close	1.531	1.252–1.871		1.282	1.025–1.603
Positive	2.962	2.287–3.836		1.794	1.317–2.445
Histologic grade			< 0.001			0.613
Well differentiated	1			1
Moderately differentiated	1.542	1.207–1.970		1.149	0.863–1.531
Poorly differentiated	2.203	1.647–2.946		1.174	0.826–1.670
pTestatus (AJCCf 8th Edition)	1		< 0.001	1		< 0.001
pT1	1.632	1.266–2.104		1.323	1.001–1.749
pT2	2.582	2.008–3.320		1.543
pT3	4.076	3.212–5.173		2.183	1.129–2.111
pT4					1.588–3.001
pNg status (AJCC 8th Edition)			< 0.001			< 0.001
pN0	1			1
pN1	1.527	1.148–2.031		1.622	1.179–2.232
pN2	2.206	1.710–2.846		2.138
pN3	5.461	4.409–6.765		3.628	1.578–2.896 2.708–4.860
Adjuvant treatment			< 0.001			< 0.001
None	1			1
Radiotherapy	1.412	1.181–1.689		0.576	0.456–0.727
Chemoradiotherapy	2.208	1.686–2.892		0.523	0.374–0.733
SIRI			< 0.001			< 0.001
≤ 1.0	1			1
1.0–1.9	1.543	1.273–1.871		1.323	1.074–1.630
≥ 1.9	2.485	2.017–3.061		1.685	1.329–2.135

^a-SIRI: Systemic Inflammation Response Index;

^b-HR: hazard ratio;

^c-CI: confidence interval;

^d-WUHNCI: Washington University Head and Neck Comorbidity Index;

^e-pT: pathological tumor;

^f-AJCC: American Joint Committee on Cancer;

^g-pN: pathological nodal.