Table 1:

Characteristics of Breast Cancer Patients Diagnosed 2007–2013, According to Endocrine Therapy Use

Covariate	Level	Total Cohort	Endocrine Therapy Initiation						HR (95% CI)	p value*
		N=21,894	Yes N=17,512			No N=4,382
Age at Diagnosis	68–74	9,308 (42.5%)	8,133	46.4%		1,175	26.8%		ref
	75–84	9,659 (44.1%)	7,588	43.3%		2,071	47.3%		0.91 (0.88–0.94)	<.001
	85–94	2,831 (12.9%)	1,744	10.0%		1,087	24.8%		0.64 (0.60–0.67)	<.001
	95+	96 (0.4%)	47	0.3%		49	1.1%		0.44 (0.33–0.59)	<.001
Race	Asian	950 (4.3%)	781	4.5%		169	3.9%		1.11 (1.04–1.20)	0.004
	Black	1,315 (6.0%)	1,083	6.2%		232	5.3%		0.99 (0.93–1.05)	0.77
	Other	149 (0.7%)	119	0.7%		30	0.7%		1.02 (0.85–1.22)	0.83
	White	19,480 (89.0%)	15,529	88.7%		3,951	90.2%		ref
Ethnicity	Hispanic	1,166 (5.3%)	983	5.6%		183	4.2%		1.03 (0.97–1.10)	0.33
	Non- Hispanic	20,728 (94.7%)	16,529	94.4%		4,199	95.8%		ref
Year of Diagnosis	2007	1,961 (9.0%)	1,528	8.7%		433	9.9%		ref
	2008	2,968 (13.6%)	2,312	13.2%		656	15.0%		0.99 (0.93–1.06)	0.76
	2009	3,144 (14.4%)	2,473	14.1%		671	15.3%		1.01 (0.95–1.08)	0.72
	2010	3,131 (14.3%)	2,525	14.4%		606	13.8%		1.13 (1.06–1.20)	<.001
	2011	3,300 (15.1%)	2,664	15.2%		636	14.5%		1.18 (1.10–1.25)	<.001
	2012	3,492 (15.9%)	2,832	16.2%		660	15.1%		1.17 (1.10–1.25)	<.001
	2013	3,898 (17.8%)	3,178	18.1%		720	16.4%		1.21 (1.14–1.29)	<.001
Stage at Diagnosis	1	13,194 (60.3%)	10,046	57.4%		3,148	71.8%		ref
	2	6,534 (29.8%)	5,596	32.0%		938	21.4%		1.13 (1.10–1.17)	<.001
	3	1,516 (6.9%)	1,378	7.9%		138	3.1%		1.07 (1.01–1.13)	0.02
	4	201 (0.9%)	181	1.0%		20	0.5%		1.50 (1.29–1.74)	<.001
	Unknown	449 (2.1%)	311	1.8%		138	3.1%		0.82 (0.73–0.92)	<.001
Receptor Status	ER+PR+	18,789 (85.8%)	15,095	86.2%		3,694	84.3%		1.16 (1.11–1.21)	<.001
	ER+PR−	3,105 (14.2%)	2,417	13.8%		688	15.7%		ref
Endocrine Therapy Class Used	AIs	13,659 (62.4%)	13,659	78.0%		0	0.0%		n/a
	Both	1,903 (8.7%)	1,903	10.9%		0	0.0%
	None	4,382 (20.0%)	0	0.0%		4,382	100.0%
	SERMs	1,950 (8.9%)	1,950	11.1%		0	0.0%
Adjusted NCI Comorbidity Score	Mean (Median)	2.1 (2.0)	2.0	2.0		2.2	2.0		0.99 (0.98–1.00)	0.01
Any Mental Illness	N (%)	5,459 (24.9%)	4,232	24.2%		1,227	28.0%		0.95 (0.92–0.98)	0.003
Emotional Disorders:
Unipolar Depression	N (%)	2,418 (11.0%)	1,876	10.7%		542	12.4%		0.95 (0.90–0.99)	0.03
Anxiety	N (%)	2,089 (9.5%)	1,651	9.4%		438	10.0%		1.00 (0.95–1.05)	0.87
Adjustment	N (%)	81 (0.4%)	62	0.4%		19	0.4%		0.93 (0.72–1.19)	0.56
Cognitive Disorders:
Delirium	N (%)	515 (2.4%)	365		2.1%	150		3.4%	0.85 (0.77–0.94)	0.002
Dementia	N (%)	1,017 (4.6%)	690		3.9%	327		7.5%	0.82 (0.76–0.88)	<.001
Personality	N (%)	59 (0.3%)	38		0.2%	21		0.5%	0.77 (0.56–1.07)	0.12
Mania and Psychoses:
Bipolar Depression	N (%)	265 (1.2%)	198		1.1%	67		1.5%	0.85 (0.74–0.98)	0.02
Schizophrenia	N (%)	185 (0.8%)	144		0.8%	41		0.9%	0.99 (0.84–1.17)	0.94
Non-Schizophrenia Psychosis	N (%)	1,004 (4.6%)	755		4.3%	249		5.7%	0.89 (0.83–0.96)	0.003
Substance Use:
Drug Use	N (%)	970 (4.4%)	774		4.4%	196		4.5%	0.99 (0.92–1.06)	0.69
Alcohol Use	N (%)	75 (0.3%)	57		0.3%	18		0.4%	1.01 (0.78–1.31)	0.96
Follow-Up Days	Mean (Median)	1,377.9 (1,280.0)	1,382.8		1,280.0	1,358.2		1,242.0	0.98 (0.97–0.99) (per 1 year change)	<.001
Number Who Initiated			17,512						n/a
Days to Initiation	Mean (Median)		156.6		120.0
Number Who Discontinued			4,503						n/a
aDays to Discontinuation	Mean (Median)		701.5		521.0
Number with 1+ years Endocrine Therapy Use			14,517						n/a
bAverage Adherence (PDC)	Mean (Median)		0.84		0.90
Percent With 0.80 or Higher			72.0

Proportion of Days Covered (PDC).

^aDiscontinuation analyzed for the first 5 years of endocrine therapy use.

^bAverage adherence calculated for patients with 1+ years of endocrine therapy use observed, and less than half of follow-up spent hospitalized or in skilled nursing facilities.

^*p values calculated from bivariable Cox regression.