Table 1. Patient characteristics in study cohort.

Characteristic	All colonoscopies		Screening colonoscopies
	n	%	n	%
Total	104,618	-	46,930	44.87
Site
Central Illinois Endoscopy	12,116	11.6	5,992	12.8
Kaiser Permanente Washington	10,875	10.4	3,476	7.4
University of North Carolina	16,641	15.9	7,893	16.8
UPMC	64,986	62.1	29,572	63.0
Sex
Male	48,065	45.9	20,982	44.7
Female	55,325	52.9	25,356	54.0
Missing	1,229	1.2	595	1.3
Age
40-492	8,485	8.1	2,300	4.9
50-59	37,936	36.3	23,359	49.8
60-69	35,121	33.6	15,213	32.4
70 and over	22,814	21.8	6,015	12.8
Missing	263	0.3	46	0.1
Race1
White	62,295	76.3	27,850	74.3
Black	8,342	10.2	4,172	11.1
Other	6,455	5.6	3,153	8.4
Missing	4,535	7.9	2,290	6.1
Insurance
Medicare	38,065	37.6	12,386	27.3
Private	56,639	56.0	29,790	65.7
Medicaid	5,451	5.4	2,592	5.7
Other	1,030	1.0	546	1.2
Indication
Screening, no family history	36,989	35.4	36,989	78.8
Screening, with family history3	9,944	9.5	9,944	21.2
Surveillance	32,974	31.5	-	-
Diagnostic	22,013	21.0	-	-
Missing	2,698	2.6	-	-
Fraction with a pathology report
Yes	64,688	61.8	25,948	55.3
No	39,930	38.2	20,985	44.7

Notes:

¹Race data not available for 2 of the 4 clinical sites and therefore was not used in other analyses.

²Patients are classified as having a family history if they have any relative with a history of colorectal cancer or an adenoma.

³Among 40- to 49-year-olds with screening colonoscopies, 68% were with family history and 32% were without family history