Insurance-Based Differences in Time to Diagnostic Follow-up after Positive Screening Mammography

Danielle D. Durham; Whitney R. Robinson; Sheila S. Lee; Stephanie B. Wheeler; Katherine E. Reeder-Hayes; J. Michael Bowling; Andrew F. Olshan; Louise M. Henderson

doi:10.1158/1055-9965.EPI-16-0148

DOI: 10.1158/1055-9965.EPI-16-0148 Published November 2016

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Figure 1.
Comparison of the Kaplan–Meier estimates of the time-to-event curve stratified by insurance status for women less than 65 years old receiving a positive screening mammogram between 1995–2010. Tick marks represent observations in time as each woman experiences the follow-up event.
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Figure 2.
Comparison of the Kaplan–Meier estimates of the time-to-event curve stratified by insurance status for women 65 years and older receiving a positive screening mammogram between 1995–2010. Tick marks represent observations in time as each woman experiences the follow-up event.

Table 1.

Demographic distribution of women ages 40 years and older receiving a positive screening mammogram between 1995–2010 by insurance status stratifying by women younger than 65 years and women 65 years and older

		Insurance status
	All	No insurance^a	Medicaid only	Medicare only	Medicare & Medicaid	Medicare & private	Private only
	n (%)	n (%)	n (%)	n (%)	n (%)	n (%)	n (%)
Age <65 y
Total	31,194	916 (3)	934 (3)	634 (2)	475 (1)	592 (2)	27,643 (89)
Race/Ethnicity
Black, non-Hispanic	3,916 (13)	144 (16)	374 (40)	165 (26)	178 (37)	108 (18)	2,947 (11)
White, non-Hispanic	24,969 (80)	665 (73)	458 (49)	423 (67)	269 (57)	444 (75)	22,710 (82)
Other	859 (3)	82 (9)	40 (4)	^b	^b	15 (3)	703 (3)
Unknown	1,450 (5)	25 (3)	62 (7)	^b	^b	25 (4)	1,283 (5)
Age, y
40–44	7,307 (23)	212 (23)	276 (30)	64 (10)	62 (13)	35 (6)	6,658 (24)
45–49	7,040 (22)	220 (24)	204 (22)	98 (15)	97 (20)	72 (12)	6,349 (23)
50–54	6,648 (21)	184 (20)	184 (20)	121 (19)	105 (22)	109 (18)	5,945 (22)
55–59	5,590 (18)	144 (16)	159 (17)	165 (26)	109 (23)	162 (27)	4,851 (18)
60–64	4,609 (15)	156 (17)	111 (12)	186 (29)	102 (21)	214 (36)	3,840 (14)
Education
<High school	1,580 (5)	140 (15)	227 (24)	107 (17)	141 (30)	59 (10)	906 (3)
High school/GED	6,692 (21)	295 (32)	273 (29)	204 (32)	142 (30)	183 (31)	5,595 (20)
Some college	7,286 (23)	206 (22)	167 (18)	130 (21)	64 (13)	140 (24)	6,579 (24)
College graduate	8,372 (27)	103 (11)	59 (6)	48 (8)	25 (5)	103 (17)	8,034 (29)
Unknown	7,264 (23)	172 (19)	208 (22)	145 (23)	103 (22)	107 (18)	6,529 (24)
Age 65+ y
Total	11,832	—	192 (2)	2,617 (22)	753 (6)	7,087 (60)	1,183 (10)
Race/Ethnicity
Black, non-Hispanic	1,226 (10)	—	46 (24)	363 (14)	285 (38)	422 (6)	110 (9)
White, non-Hispanic	9,883 (83)	—	132 (69)	2,115 (81)	408 (54)	6,245 (88)	983 (83)
Other	134 (1)	—	^b	27 (1)	^b	71 (1)	19 (2)
Unknown	589 (5)	—	^b	112 (4)	^b	349 (5)	71 (6)
Age, y
65–69	4,342 (37)	—	80 (42)	920 (35)	222 (29)	2,354 (33)	766 (65)
70–74	3,320 (28)	—	49 (26)	753 (29)	204 (27)	2,086 (29)	228 (19)
75+	4,170 (35)	—	63 (33)	944 (36)	327 (43)	2,647 (37)	189 (16)
Education
<High school	1,632 (14)	—	62 (32)	457 (17)	297 (39)	705 (10)	111 (9)
High school/GED	3,767 (32)	—	58 (30)	892 (34)	195 (26)	2,277 (32)	345 (29)
Some college	2,291 (19)	—	20 (10)	403 (15)	65 (9)	1,564 (22)	239 (20)
College graduate	1,579 (13)	—	17 (9)	267 (10)	25 (3)	1,106 (16)	164 (14)
Unknown	2,563 (22)	—	35 (18)	598 (23)	171 (23)	1,435 (20)	324 (27)

↵^aWomen reporting no insurance 65 years and older were removed from the models due to small sample size (n = 24).
↵^bCell counts < 11 have been suppressed.

Table 2.

Median and mean time to initial diagnostic follow-up in days, proportion with follow-up greater than 60 days, and proportion with no follow-up for women ages 40 years and older receiving a positive screening mammogram between 1995–2010 by insurance status, stratified at 65 years of age

Insurance status	Median (IQR)^a	Mean (SD)	Percentage with follow-up > 60 d	Percentage with no follow-up within 365 d
All	12 (7–22)	43 (116)	11.9	10.1
Age <65 y
No insurance	16 (8–37)	62 (166)	17.5	13.8
Medicaid only	14 (7–27)	47 (121)	12.9	8.5
Medicare only	15 (8–28)	53 (159)	15.5	9.6
Medicare & Medicaid	14 (8–29)	60 (220)	14.0	9.5
Medicare & private	13 (7–24)	42 (80)	13.0	8.2
Private only	12 (7–21)	40 (108)	11.0	10.9
All, <65	12 (7–22)	41 (114)	11.4	10.8
Age 65+ y
Medicare only	13 (7–26)	54 (135)	14.5	8.8
Medicare & Medicaid	14 (8–29)	55 (142)	15.9	8.8
Medicare & private	12 (7–21)	44 (118)	12.5	7.7
Private only	12 (7–21)	40 (87)	11.5	10.6
All, 65+	13 (7–22)	46 (121)	13.2	8.3

↵^aIQR reported as a range; from the 25^th percentile to the 75^th percentile.

Table 3.

Unadjusted and adjusted HR estimates and 95% CIs of the association between insurance status and time to initial diagnostic follow-up after a positive screening mammogram for women younger than 65 years and women 65 years and older between 1995–2010

	Unadjusted		Adjusted^b
Insurance status	HR (95% CI)	P^a	HR (95% CI)	P^a
Age <65 y
No insurance	0.59 (0.33–1.06)	0.08	0.47 (0.25–0.89)	0.02
Medicaid only	0.75 (0.44–1.28)	0.28	0.81 (0.46–1.42)	0.46
Medicare only	0.86 (0.44–1.67)	0.65	0.95 (0.47–1.91)	0.88
Medicare & Medicaid	0.63 (0.32–1.24)	0.18	0.50 (0.24–1.02)	0.06
Medicare & private	2.16 (1.07–4.38)	0.03	1.81 (0.86–3.83)	0.12
Private only (referent)	1.00 (—)	—	1.00 (—)	—
Age 65+ y
Medicare only	0.89 (0.66–1.20)	0.44	0.97 (0.70–1.34)	0.83
Medicare & Medicaid	0.79 (0.49–1.27)	0.33	0.99 (0.57–1.74)	0.99
Medicare & private (referent)	1.00 (—)	—	1.00 (—)	—
Private only	1.92 (1.22–3.03)	0.005	2.09 (1.27–3.44)	<0.01

↵^aAll P values are 2-sided, and α < 0.05 was considered statistically significant.
↵^bThe adjusted model includes race, education, breast density, categorical age, history of breast biopsy, family history of breast cancer, and facility type.

Table 4.

Unadjusted and adjusted OR estimates and 95% CIs of the association between insurance status and time to initial diagnostic follow-up of more than 60 days after a positive screening mammogram for women younger than 65 years and women 65 years and older between 1995–2010

	Unadjusted		Adjusted^b
Insurance status	OR (95% CI)	P^a	OR (95% CI)	P^a
Age <65 y
No insurance	1.61 (1.38–1.89)	<0.0001	1.59 (1.31–1.94)	<0.0001
Medicaid only	0.97 (0.82–1.14)	0.70	1.00 (0.82–1.21)	0.96
Medicare only	1.19 (0.98–1.43)	0.08	1.21 (0.97–1.52)	0.09
Medicare & Medicaid	1.09 (0.88–1.36)	0.43	1.09 (0.85–1.42)	0.49
Medicare & private	0.95 (0.77–1.17)	0.62	1.10 (0.87–1.40)	0.43
Private only (referent)	1.00 (—)	—	1.00 (—)	—
Age 65+ y
Medicare only	1.21 (1.08–1.35)	0.001	1.14 (0.99–1.30)	0.06
Medicare & Medicaid	1.29 (1.08–1.56)	0.006	0.96 (0.76–1.20)	0.73
Medicare & private (referent)	1.00 (—)	—	1.00 (—)	—
Private only	1.12 (0.96–1.31)	0.16	1.14 (0.95–1.36)	0.16

↵^aAll P values are 2-sided, and α < 0.05 was considered statistically significant.
↵^bThe adjusted model includes race, education, breast density, categorical age, history of breast biopsy, family history of breast cancer, and facility type.