Table 1.
Characteristics of heart failure cases and matched controls
| Cases (n = 102) | Controls (n = 306) | P‐value* | |
|---|---|---|---|
| Age at breast cancer diagnosisa | |||
| Median age (years) | 51.1 [45.1–55.2] | 51.1 [45.5–55.2] | |
| 30–39 years | 12 (11.8) | 36 (11.8) | |
| 40–49 years | 31 (30.4) | 93 (30.4) | |
| 50–59 years | 48 (47.1) | 144 (47.1) | |
| 60–65 years | 11 (10.8) | 33 (10.8) | |
| Year of breast cancer diagnosisa | |||
| 1976–1979 | 12 (11.8) | 41 (13.4) | |
| 1980–1989 | 26 (25.5) | 83 (27.1) | |
| 1990–1999 | 32 (31.4) | 85 (27.8) | |
| 2000–2009 | 32 (31.4) | 97 (31.7) | |
| Type of surgery | |||
| Breast conserving surgery | 38 (37.3) | 167 (54.6) | |
| Mastectomy | 64 (62.8) | 139 (45.4) | <0.001 |
| Radiotherapy | |||
| No | 14 (13.7) | 38 (12.4) | |
| Yes | 88 (86.3) | 268 (87.6) | 0.75 |
| Chemotherapy | |||
| No chemotherapy | 44 (43.1) | 185 (60.5) | |
| Chemotherapy, no trastuzumab | 44 (43.1) | 111 (36.3) | |
| Chemotherapy and trastuzumab | 14 (13.7) | 10 (3.3) | |
| No chemotherapy, trastuzumab | 0 (0) | 0 (0) | <0.001 |
| Endocrine therapy | |||
| No | 65 (63.7) | 241 (78.8) | |
| Yes | 37 (36.3) | 65 (21.2) | 0.002 |
| Age at HF diagnosis/cut‐off dateb | |||
| Median age (years) | 62.1 [53.8–69.2] | 62.1 [53.8–69.2] | |
| <40 years | 3 (2.9) | 10 (3.3) | |
| 40–49 years | 13 (12.8) | 38 (12.4) | |
| 50–59 years | 24 (23.5) | 72 (23.5) | |
| 60–69 years | 37 (36.3) | 111 (36.3) | |
| ≥70 years | 25 (24.5) | 75 (24.5) | |
| Time to HF/cut‐off datea | |||
| Median time (years) | 10.9 [3.5–18.4] | 10.9 [3.5–18.4] | |
| <1 year | 6 (5.9) | 18 (5.9) | |
| 1–4 years | 22 (21.6) | 66 (21.6) | |
| 5–9 years | 17 (16.7) | 51 (16.7) | |
| 10–14 years | 19 (18.6) | 56 (18.3) | |
| 15–19 years | 18 (17.7) | 55 (18.0) | |
| ≥20 years | 20 (19.6) | 60 (19.6) | |
Values are expressed as n (%), or median [interquartile range].
HF, heart failure; IQR, interquartile range.
a
Matching factor for control selection.
b
The variable ‘age at HF diagnosis/cut‐off date’ is derived from matching factors ‘age at breast cancer diagnosis’ and ‘time to HF/cut‐off date’. Cut‐off date was defined as date of HF diagnosis for cases, and for controls as the date of breast cancer plus the time interval between breast cancer and HF diagnosis for the corresponding case.
*
P‐value for difference in non‐matching variables between cases and controls, calculated using a conditional model (accounting for matching variables).