Table 3. Multivariate analysis of overall survival of patients with OSCC.

Variable		Model 1	Model 2	Model 3	Model 4
		HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)
Sex	Male	1 ref	1 ref	1 ref	1 ref
	Female	0.819 (0.566,1.186)	0.874 (0.598,1.278)	0.950 (0.630,1.433)	0.966 (0.634,1.471)
Age	> 60 yr	1 ref	1 ref	1 ref	1 ref
	≤ 60 yr	1.029 (0.759,1.394)	1.039 (0.764,1.413)	0.980 (0.716,1.34)	0.987 (0.719,1.354)
Smoking history	Never	1 ref	1 ref	1 ref	1 ref
	Ever	0.885 (0.59,1.327)	0.943 (0.631,1.409)	0.784 (0.518,1.187)	0.876 (0.580,1.324)
Drinking history	Never	1 ref	1 ref	1 ref	1 ref
	Ever	0.909 (0.616,1.342)	0.876 (0.595,1.291)	0.949 (0.641,1.405)	0.910 (0.616,1.342)
Location	Buccal mucosa	1 ref	1 ref	1 ref	1 ref
	Tongue	1.564 (0.97,2.522)	1.569 (0.970,2.538)	1.615 (0.986,2.647)	1.646 (1.002,2.703)
	Gingiva	1.562 (0.935,2.609)	1.570 (0.939,2.625)	1.447 (0.840,2.491)	1.444 (0.834,2.498)
	Others*	1.682 (1.035,2.735)	1.686 (1.035,2.749)	1.685 (1.022,2.779)	1.687 (1.026,2.775)
Cell differentiation	High			1 ref	1 ref
	Moderate			0.833 (0.578,1.199)	0.887 (0.615,1.279)
	Low			1.189 (0.697,2.029)	1.272 (0.748,2.164)
Tumor stage	T1			1 ref	1 ref
	T2			0.768 (0.427,1.382)	0.794 (0.441,1.429)
	T3			0.767 (0.395,1.49)	0.872 (0.447,1.701)
	T4			1.15 (0.586,2.256)	1.204 (0.615,2.357)
Lymph node metastasis	No			1 ref	1 ref
	Yes			1.907 (1.095,3.322)	1.723 (0.833,3.565)
TNM stage	I			1 ref	1 ref
	II			1.929 (0.936,3.976)	1.723 (0.833,3.565)
	III			1.449 (0.621,3.377)	1.160 (0.491,2.743)
	IV			1.412 (0.545,3.658)	1.108 (0.425,2.890)
KDM4A	Low expression		1 ref		1 ref
	High expression		2.426 (1.177,3.311)		2.191 (1.592,3.016)

Abbreviations: HR, Hazard Ratio.

Others* included floor of mouth, lips and palate.