Table 1.

Sociodemographic and Imaging Characteristics of Patients in Medicare

Characteristics	Mean per Year* n (%)	Range (Min – Max)
Medicare**	1,219,614	1,174,633 – 1,274,441
Age	76	75 – 76
Sex
Male	508,825 (41.7)	477,532 – 544,438
Female	710,789 (58.3)	689,931 – 730,003
Race
White	1,010,493 (82.9)	984,320 – 1,039,693
Black	95,587 (7.8)	91,007 – 99,830
Other	113,534 (9.3)	90,448 – 138,101
Charlson-Deyo Comorbidity Index	1.6	1.43 – 1.75
Rural-Urban Continuum***
Metro	1,026,731 (84.2)	983,019 – 1,078,506
Adjacent to Metro	107,770 (8.8)	104,317 – 110,129
Not Adjacent to Metro	85,113 (7.0)	82,503 – 86,000
Education High School or Above***	85.4	85.3 – 85.4
Median Household Income***	$57,283	56,951 – 57,682
Imaging
None	1,095,294 (89.9)	1,041,326 – 1,144,333
Other Imaging	116,440 (9.5)	65,344 – 211,632
Thyroid Ultrasound	7,880 (0.6)	1,967 – 21,483

^*Mean per year is the aggregate of the means of all 12 years at the patient-level.

^**The cohort includes the 20% Medicare sample residing in the regional subgroups that correspond with SEER-Medicare counties.

^***Data is measured at the zip code level. All other variables are measured at the individual level.