Table 1.

Factors Associated with Repeat Colonoscopy at 1, 3 and 5 Years in 12,998 Medicare Beneficiaries

Variable	N (%)	Colonoscopy Year 1 (%)	P Value	Colonoscopy Year 3 (%)	P Value	Colonoscopy Year 5 (%)	P Value
Age Group
70–74	4050 (31.7)	6.9	0.17	25.3	0.37	50.5	<0.0001
75–79	4666 (36.5)	7.7		26.7		47.3
80–84	2697 (21.1)	8.9		25.4		42.7
≥ 85	1358 (10.6)	9.6		22.6		31.4
Gender
Female	7196 (56.3)	8.0	0.02	24.7	0.03	43.6	0.0001
Male	5575 (46.7)	7.8		27.2		49.5
Race
White	11036 (86.4)	7.6	0.002	25.4	0.0009	46.2	0.02
Black	666 (5.2)	11.3		34.3		53.8
Other	847 (6.6)	9.1		25.7		42.6
Unknown	222 (1.7)	7.7		25.6		48.3
Procedure Year
2001	3240 (25.4)	9.3	0.0004	34.7	<0.0001	57.4	<0.0001
2002	3412 (26.7)	7.9		26.3		48.6
2003	3270 (25.6)	7.9		22.5		42.7
2004	2849 (22.3)	6.4		19.1		36.2
Comorbidity
0	7063 (55.3)	7.2	0.0004	24.6	<0.0001	45.8	0.38
1	3389 (26.5)	7.9		26.3		47.7
≥ 2	2319 (18.2)	10.0		29.2		45.3
Increased risk *
Yes	3139 (24.6)	7.9	0.89	32.8	<0.0001	61.3	<0.0001
No	9632 (75.4)	7.9		23.6		41.2
Prior Colonoscopy
Yes	2863 (22.4)	8.6	0.003	35.6	<0.0001	65.3	<0.0001
No	9908 (77.6)	7.7		23.2		41.2
Specialty
Gastroenterology	8288 (64.9)	7.7	0.12	25.5	0.02	46.1	0.17
Family medicine	1558 (12.2)	8.9		30.5		53.5
Internal medicine	1226 (9.6)	8.8		29.2		45.1
General surgery	1060 (8.3)	6.8		26.0		42.1
Colorectal surgery	243 (1.9)	8.1		24.9		50.3
Unknown	396 (3.1)	7.8		18.7		48.9
Geographic region
Northeast	3697 (28.9)	7.4	<0.00001	25.7	0.002	46.1	<0.0001
South	2060 (16.1)	8.6		31.1		53.5
Midwest	1431 (11.2)	7.5		24.6		45.2
West	4112 (32.2)	7.6		23.2		42.1
Other	1471 (11.5)	9.0		27.5		50.3
Income Quintile
1	3113 (24.4)	8.9	<0.0001	28.8	0.01	48.2	0.06
2	3130 (24.5)	8.3		26.5		46.8
3	3120 (24.4)	7.1		23.4		44.3
4	3125 (24.5)	7.4		25.1		45.7
Education Quintile
1	3122 (24.4)	8.9	0.02	29.2	0.007	48.3	0.15
2	3119 (24.4)	7.4		26.1		44.5
3	3123 (24.5)	8.5		25.2		46.8
4	3124 (24.5)	6.9		23.6		45.3

^*Increased risk includes prior history of polyps, or family history of cancer.