Table II.

Univariate and multivariate analysis for the clinical predictors of level Ib metastasis.

	Univariate analysis			Multivariate analysis
Characteristic	Level Ib metastasis (−)	Level Ib metastasis (+)	P-value	Hazard ratio	95% confidence interval	P-value
Age
≤45 years	557	33	0.708	-	-	-
>45 years	521	34
Gender
Male	809	55	0.241	0.630	0.322–1.232	0.177
Female	269	12
Histology
WHO I	10	0	1.000	-	-	-
WHO II/III	1068	67
T stage
T1	240	11	0.240	0.813	0.580–1.139	0.229
T2	436	30
T3	209	18
T4	193	8
N stage
N0	317	0	<0.001a	-	-	-
N1	506	27
N2	184	23
N3	71	17
Nasal cavity involvement
No	866	52	0.635	1.288	0.665–2.495	0.453
Yes	212	15
Maxillary sinus involvement
No	1033	45	0.515	0.420	0.049–3.623	0.430
Yes	66	1
Carotid sheath involvement
No	544	20	0.001a	2.106	1.204–3.682	0.009a
Yes	534	47
Neck lymph node level involvement
No	327	0	<0.001a	6.965	3.866–12.548	<0.001a
Level II/III	708	49
Level IV	43	18
Maximum neck lymph node diameter
<20 mm	449	6	<0.001a	2.212	0.907–5.394	0.081a
≥20 mm	629	61

WHO, World Health Organization.

^aStatistically significant.