Table 2.

Univariate and multivariable multinomial logistic regression analysis of 1,990 conventional papillary thyroid carcinomas using category VI as the reference

Variable	Univariate multinomial				Multivariable multinomial
	Category III (n=98)	P-value	Category V (n=730)	P-value	Category III (n=98)	P-value	Category V (n=730)	P-value
	OR (95% CI)		OR (95% CI)		OR (95% CI)		OR (95% CI)
Age (yr)	1.018	0.040	1.001	0.851	1.013	0.159	0.998	0.626
	(1.001-1.035)		(0.993-1.008)		(0.995-1.031)		(0.990-1.006)
Sex		0.259		0.537		0.118		0.902
Male	1.311		0.931		1.469		1.015
	(0.820-2.097)		(0.741-1.169)		(0.907-2.380)		(0.803-1.282)
Female	1 (Ref.)		1 (Ref.)		1 (Ref.)		1 (Ref.)
US assessment		0.005		0.320		0.007		0.312
Suspicious	0.286		0.742		0.296		0.734
	(0.120-0.679)		(0.412-1.336)		(0.121-0.720)		(0.403-1.336)
Probably benign	1 (Ref.)		1 (Ref.)		1 (Ref.)		1 (Ref.)
Tumor size (mm)	0.917	<0.001	0.957	<0.001	0.934	0.007	0.969	<0.001
	(0.875-0.962)		(0.942-0.973)		(0.889-0.981)		(0.952-0.986)
Gross ETE		0.041		<0.001		0.261		0.059
Yes	0.229		0.438		0.432		0.643
	(0.056-0.943)		(0.285-0.674)		(0.100-1.869)		(0.406-1.017)
No	1 (Ref.)		1 (Ref.)		1 (Ref.)		1 (Ref.)
Central LNM		<0.001		<0.001		0.008		0.020
Yes	0.391		0.664		0.487		0.780
	(0.241-0.632)		(0.548-0.804)		(0.287-0.827)		(0.633-0.962)
No	1 (Ref.)		1 (Ref.)		1 (Ref.)		1 (Ref.)
Lateral LNM		0.170		0.001		0.468		0.456
Yes	0.576		0.574		1.383		0.870
	(0.261-1.267)		(0.411-0.801)		(0.577-3.312)		(0.603-1.255)
No	1 (Ref.)		1 (Ref.)		1 (Ref.)		1 (Ref.)
Multiplicity		0.350		0.041		0.785		0.375
Yes	0.807		0.812		0.937		0.911
	(0.514-1.266)		(0.665-0.991)		(0.588-1.494)		(0.741-1.120)
No	1 (Ref.)		1 (Ref.)		1 (Ref.)		1 (Ref.)

OR, odds ratio; CI, confidence interval; US, ultrasonography; ETE, extrathyroidal extension; LNM, lymph node metastasis; Ref., Reference.