Table 3.

Multivariable Cox Proportional Hazard Models for Thyroid Specific Mortality Among California Differentiated Thyroid Cancers with Total or Near-Total Thyroidectomy, 1991–2008

	Males			Females
	HR	CI	p	HR	CI	p
Neck reoperation
No	REF	—	—	REF	—	—
Yes	2.90	[2.13–3.96]	<0.001	6.29	[4.86–8.14]	<0.001
Initial treatment
No radioiodine	REF	—	—	REF	—	—
Radioiodine	0.60	[0.47–0.75]	<0.001	0.88	[0.73–1.07]	0.22
Race/ethnicity
NH white	REF	—	—	REF	—	—
NH African American	0.43	[0.21–0.89]	0.02	1.62	[1.02–2.56]	0.04
Hispanic	0.95	[0.70–1.28]	0.72	1.28	[1.00–1.64]	0.05
NH Asian/Pacific Islander	0.82	[0.58–1.15]	0.24	1.21	[0.94–1.56]	0.13
Other/unknown	1.28	[0.17–9.46]	0.81	0.96	[0.30–3.07]	0.95
Age at diagnosis (years)
15–34	0.05	[0.03–0.11]	<0.001	0.01	[0.00–0.02]	<0.001
35–44	0.12	[0.07–0.21]	<0.001	0.05	[0.03–0.08]	<0.001
45–54	0.32	[0.21–0.49]	<0.001	0.13	[0.09–0.20]	<0.001
55–64	0.51	[0.34–0.77]	0.001	0.43	[0.32–0.59]	<0.001
65–74	0.82	[0.57–1.17]	0.27	0.63	[0.49–0.82]	<0.001
≥75	REF	—	—	REF	—	—
Year of diagnosis
1991–1993	2.00	[1.13–3.54]	0.02	2.14	[1.28–3.59]	0.004
1994–1996	1.87	[1.18–2.94]	0.007	1.82	[1.24–2.69]	0.002
1997–1999	1.75	[1.13–2.70]	0.01	1.99	[1.39–2.84]	<0.001
2000–2002	1.08	[0.70–1.67]	0.72	1.35	[0.93–1.95]	0.12
2003–2005	1.16	[0.76–1.78]	0.49	1.08	[0.75–1.57]	0.68
2006–2008	REF	—	—	REF	—	—
Histology
Papillary	0.64	[0.47–0.88]	0.006	0.52	[0.41–0.66]	<0.001
Follicular	REF	—	—	REF	—	—
N stage at diagnosis
N0	REF	—	—	REF	—	—
N1	1.25	[0.94–1.67]	0.13	1.72	[1.35–2.20]	<0.001
Unknown	1.63	[1.14–2.31]	0.007	1.68	[1.27–2.23]	<0.001
M stage at diagnosis
M0	REF	—	—	REF	—	—
M1	6.21	[4.48–8.61]	<0.001	3.16	[2.33–4.28]	<0.001
Unknown	1.01	[0.66–1.55]	0.97	1.05	[0.74–1.48]	0.80
Tumor size
<1 cm	REF	—	—	REF	—	—
1–2 cm	1.42	[0.79–2.57]	0.24	1.22	[0.76–1.96]	0.42
2–3 cm	2.37	[1.36–4.11]	0.002	2.09	[1.33–3.29]	0.002
3–4 cm	3.32	[1.89–5.83]	<0.001	3.62	[2.27–5.76]	<0.001
>4 cm	5.06	[3.03–8.45]	<0.001	4.47	[2.86–6.99]	<0.001
Unknown	3.92	[2.23–6.89]	<0.001	4.01	[2.51–6.39]	<0.001
Extrathyroidal extension
No	REF	—	—	REF	—	—
Yes	3.64	[2.75–4.80]	<0.001	4.32	[3.39–5.49]	<0.001
Unknown	2.28	[1.38–3.75]	0.001	2.37	[1.52–3.71]	<0.001
Comorbidities at diagnosisa
No admission ≤2 years of diagnosis	1.80	[1.21–2.68]	0.004	1.20	[0.88–1.64]	0.25
0	REF	—	—	REF	—	—
1–2	1.37	[0.89–2.10]	0.15	1.44	[1.04–2.00]	0.03
≥3	2.26	[1.30–3.92]	0.004	2.09	[1.40–3.12]	<0.001
Neighborhood socioeconomic status
Low	1.56	[1.23–1.98]	<0.001	0.99	[0.81–1.21]	0.92
High	REF	—	—	REF	—	—
Marital status
Never married	1.02	[0.73–1.44]	0.90	0.91	[0.65–1.26]	0.56
Previously married	0.92	[0.63–1.35]	0.67	1.18	[0.95–1.47]	0.13
Married	REF	—	—	REF	—	—
Unknown marital status	1.39	[0.61–3.17]	0.43	1.73	[0.97–3.10]	0.07
Health insurance at diagnosis
No insurance/self-pay	0.88	[0.38–2.07]	0.77	1.45	[0.75–2.79]	0.27
Private	REF	—	—	REF	—	—
Medicaid/government	1.16	[0.73–1.84]	0.54	1.53	[1.07–2.19]	0.02
Medicare	1.14	[0.83–1.56]	0.42	1.08	[0.83–1.40]	0.55
Unknown insurance	0.53	[0.34–0.82]	0.005	0.69	[0.47–1.03]	0.07
Hospital thyroidectomy volumeb
Low	REF	—	—	REF	—	—
High	1.06	[0.82–1.36]	0.66	0.92	[0.74–1.13]	0.42
Unknown	1.30	[0.90–1.88]	0.16	1.09	[0.79–1.51]	0.58

^aExlihauser comorbidity index diagnosis or two years prior to diagnosis, cancer was excluded as a comorbidity.

^bHigh-volume thyroidectomy hospital defined as the top 10% of hospitals performing thyroidectomies.

HR, hazard ratio.