Factors associated with the prescription of antidepressive medication to breast cancer patients

Figures & data

Table I. Descriptive characteristics of a cohort of 1 247 women and their breast cancers, who attended a course at a rehabilitation center (RCD) and a matched comparison group of 2 903 women who did not.

	RCD attendees		Comparison group
Characteristic	n = 1247^a	%	n = 2903^a	%	P^b
Clinical variable
Tumor size (mm)					0.88
< 20	631	(51)	1 466	(50)
≥ 20 – < 50	550	(44)	1 272	(44)
≥ 50	66	(5)	165	(6)
Tumor-positive axillary lymph nodes					<0.01
0	524	(42)	1 384	(48)
1–3	451	(36)	967	(33)
4–9	162	(13)	317	(11)
≥ 10	110	(9)	235	(8)
Postmenopausal					0.06
Yes	616	(49)	1 525	(53)
Estrogen receptor status					0.36
Positive	969	(78)	2 220	(76)
Tumor grade					0.77
I	252	(20)	587	(20)
II	478	(38)	1 071	(37)
III	307	(25)	730	(25)
Non-ductal carcinoma	188	(15)	467	(16)
Treatment-specific factors
Type of surgery					0.04
Mastectomy	674	(54)	1 524	(52)
Lumpectomy	534	(43)	1 321	(46)
Lumpectomy followed by mastectomy^c	39	(3)	58	(2)
Adjuvant treatment					0.09
None	97	(8)	247	(9)
Only chemotherapy	134	(11)	299	(10)
Only antihormonal	260	(21)	656	(23)
Only radiation	52	(4)	141	(5)
Antihormonal and chemotherapy	215	(17)	380	(13)
Chemotherapy and radiation	45	(4)	110	(4)
Antihormonal and radiation	80	(6)	195	(7)
Chemotherapy, antihormonal and radiation	40	(3)	91	(3)
Sociodemographic factors
Age (years)					0.18
< 30	6	(0)	16	(1)
30–40	116	(9)	252	(9)
40–50	395	(32)	832	(29)
50–60	440	(35)	1 041	(36)
> 60	290	(23)	762	(26)
Level of education					<0.01
Basic (7–13 years)	324	(26)	1 053	(36)
Vocational	460	(37)	1 004	(35)
Higher (> 14 years)	451	(36)	789	(27)
Income (DKK)^d					0.02
Mean	178 275		190 211
First quartile	128 485		125 140
Third quartile	213 469		217 343
Work market affiliation					0.01
Employed	885	(71)	1 906	(66)
Unemployed	79	(6)	198	(7)
Sick leave	4	(0)	17	(1)
Early retirement pension	73	(6)	248	(9)
Retired	174	(14)	441	(15)
Student/other	29	(2)	80	(3)
Cohabitation status					<0.01
Living with a partner	833	(67)	2 096	(72)
Number of children living at home					0.02
0	865	(69)	2 097	(72)
1–2	343	(28)	686	(24)
≥ 3	37	(3)	109	(4)
Charlson comorbidity index^e					0.91
0	1 077	(86)	2 519	(87)
1	107	(9)	237	(8)
> 1	63	(5)	147	(5)
Use of antidepressants before breast cancer^f, g, h	211	(17)	413	(14)	0.02
Recurrence of breast cancer	93	(7)	181	(6)	0.01
New primary cancer after breast cancer^h	10	(1)	18	(1)	<0.01

^aPatients for whom information on a variable was missing are not listed for that particular variable. For this reason, the subgroups do not add up to the total number of patients for all variables.

^bχ² test was used for categorical variables; Student t-test was used for continuous variables; and the log rank test was used for time-dependent variables.

^cIntended lumpectomy changed to mastectomy during surgery.

^dHousehold income after taxation and interest per person, adjusted for number of persons in the household and deflated according to the 2000 value of the Danish crown (DKK) by the following formula from the Danish Ministry of Finance: deflated household income/(no. of persons in household^0.6.

^eGrouped on the basis of the cumulated sum of scores 0, 1 and ≥ 2. This index provides an overall score for comorbidity based on a composite of values weighted by level of severity assigned to 19 selected conditions scored from 1 to 6.²⁷ Scores are summarized on the basis of information on hospitalizations from 1978 onward. Score 1: myocardial infarct, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, connective tissue disease, ulcer disease, mild liver disease, diabetes type 1 and diabetes type 2. Score 2: hemiplagia, moderate-to-severe renal disease, diabetes with end-organ damage type 1 or type 2. Score 3: moderate-to-severe liver disease. Score 6: AIDS.

^fTwo or more independently redeemed prescriptions of a drug with an ATC-code initiated by ‘N06A’.

^gMean follow-up of 7.04 years, 5–95% range, 1.43–10.41 years.

^hBreast cancer as defined by date of surgery.

Table II. Adjusted hazard ratios for use of antidepressant medication^a after treatment for breast cancer, in women who did not use antidepressants before the diagnosis, mutually adjusted on all covariates. RCD attendees and comparison group, n = 3513.^b

	Hazard ratio	95% CI
Clinical variable
Tumor size per cm	1.01	0.95–1.07
Tumor-positive axillary lymph nodes
≥ 1	1	–
0	0.96	0.77–1.19
per 1 extra positive	1.01	1.00–1.03
Postmenopausal
No	1	–
Yes	1.26	0.88–1.81
Estrogen receptor status
Negative	1	–
Positive	0.95	0.70–1.29
Tumor grade
I	1	–
II	1.17	0.92–1.48
III	1.18	0.90–1.55
Nonductal carcinoma	1.10	0.83–1.45
Treatment-specific factors
Type of surgery
Mastectomy	1	–
Lumpectomy	0.92	0.74–1.14
Lumpectomy and mastectomy^c	1.05	0.62–1.77
Adjuvant treatment
None	1	–
Only chemotherapy	0.89	0.63–1.25
Only antihormonal	0.84	0.63–1.13
Only radiation	0.85	0.54–1.35
Antihormonal and chemotherapy	1.02	0.78–1.34
Chemotherapy and radiation	0.71	0.44–1.17
Antihormonal and radiation	1.07	0.73–1.56
Chemotherapy, antihormonal and radiation	0.71	0.41–1.23
Sociodemographic factors
Level of education
Basic (7–13 years)	1	–
Vocational	1.13	0.93–1.37
Higher (> 14 years)	0.91	0.73–1.14
Income (DKK)^d
per 25 000	0.98	0.96–1.00
Work market affiliation
Employed	1	–
Unemployed	1.56	1.16–2.10
Sick leave^e	–	–
Early retirement pension	1.28	0.90–1.81
Retired	1.03	0.73–1.46
Student/other	0.98	0.58–1.67
Cohabitation status
Living with a partner	1	–
Not living with a partner	1.14	0.94–1.37
Number of children living at home
0	1	–
≥ 1	0.79	0.62–1.00
Charlson comorbidity index^f
No comorbidity	1	–
1	1.29	0.96–1.71
> 1	1.35	0.96–1.91
Recurrence of breast cancer
No	1	–
Yes	2.56	1.86–3.52
New primary cancer after diagnosis of breast cancer
No	1	–
Yes	3.34	1.50–7.76

^aTwo or more independently redeemed prescriptions of a drug with an ATC code starting with ‘N06A’.

^bThirteen patients could not be included in the analysis because of missing information.

^cIntended lumpectomy changed to mastectomy during surgery.

^dHousehold income after taxation and interest per person, adjusted for number of persons in the household and deflated according to the 2000 value of the Danish crown by the following formula from the Danish Ministry of Finance: deflated household income/(no. of persons in household^0.6).

^eSmall numbers did not allow calculations of hazard ratios for this covariate.

^fGrouped on the basis of the cumulated sum of scores 0, 1 and ≥ 2. This index provides an overall score for comorbidity based on composite of values weighted by level of severity assigned to 19 selected conditions scored from 1 to 6.²⁷ Scores are summarized on the basis of information on hospitalizations from 1978 onward. Score 1: myocardial infarct, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, connective tissue disease, ulcer disease, mild liver disease, diabetes type 1 and diabetes type 2. Score 2: hemiplagia, moderate-to-severe renal disease, diabetes with end-organ damage type 1 or type 2. Score 3: moderate-to-severe liver disease. Score 6: AIDS.

Figure 1. Kaplan–Meier failure plots of use of antidepressants during the first five years after diagnosis of breast cancer, among women who were not prior users; Dallund Rehabilitation Centre attendees were censored from the plot at time of course attendance.

Table III. Adjusted hazard ratios for use of antidepressant medication^a in 1 034^b breast cancer patients who did not use antidepressant medication before diagnosis and who attended a rehabilitation program after breast cancer, by time between the breast cancer diagnosis and the rehabilitation program.

Time between breast cancer diagnosis and rehabilitation program	Hazard ratio	95% CI
0–1 year	1.02	0.46–2.29
1–2 years	0.44	0.18–1.07
> 2 years	0.69	0.33–1.44

Adjusted for work market affiliation, children living at home (yes, no), income and number of tumor-positive axillary lymph nodes.

^aTwo or more independently redeemed prescriptions of a drug with an ATC code starting with ‘N06A’.

^bTwo patients could not be included in the analysis because of missing information.