Table 2.
Comparison of myocardial infarction and heart failure rates with the general population
| Myocardial infarctiona | Heart failurea | |||||||
|---|---|---|---|---|---|---|---|---|
| Observed | SIR | 95% CI | AER | Observed | SIR | 95% CI | AER | |
| Total | 394 | 1.4 | 1.3–1.6 | 8 | 396 | 1.0 | 0.9–1.1 | 0 |
| Age at breast cancer diagnosis (years) | ||||||||
| <35 | 5 | 0.9 | 0.3–2.1 | 0 | 12 | 2.7 | 1.4–4.7 | 7 |
| 35–40 | 17 | 1.1 | 0.7–1.8 | 1 | 20 | 1.4 | 0.9–2.2 | 4 |
| 40–49 | 180 | 1.5 | 1.3–1.7 | 8 | 179 | 1.1 | 1.0–1.3 | 3 |
| 50–61 | 192 | 1.4 | 1.2–1.6 | 12 | 185 | 0.8 | 0.7–1.0 | −8 |
| Calendar period of breast cancer diagnosis and follow-up interval | ||||||||
| 1970–1986 | ||||||||
| 10–19 years | 128 | 1.3 | 1.1–1.5 | 21 | 91 | 0.8 | 0.7–1.0 | −16 |
| 20+ years | 120 | 2.1 | 1.7–2.5 | 210 | 127 | 0.9 | 0.7–1.0 | −63 |
| 1987–1999 | ||||||||
| 1–9 years | 41 | 0.7 | 0.5–1.0 | -6 | 57 | 1.4 | 1.1–1.9 | 8 |
| 10–19 years | 54 | 1.7 | 1.3–2.2 | 15 | 64 | 1.1 | 0.8–1.4 | 3 |
| 20+ years | 8 | 1.7 | 0.7–3.4 | 24 | 9 | 0.8 | 0.4–1.5 | −17 |
| 2000–2009 | ||||||||
| 1–9 years | 26 | 1.5 | 1.0–2.2 | 7 | 36 | 1.5 | 1.0–2.0 | 9 |
| 10+ years | 6 | 2.0 | 0.7–4.3 | 23 | 12 | 2.6 | 1.3–4.5 | 58 |
| Radiation therapy and chemotherapy | ||||||||
| None | 29 | 0.8 | 0.5–1.1 | −5 | 33 | 0.5 | 0.4–0.8 | −16 |
| Radiation therapy alone | 264 | 1.5 | 1.4–1.7 | 12 | 233 | 0.9 | 0.7–1.0 | −5 |
| Chemotherapy alone | 6 | 2.6 | 0.9–5.5 | 13 | 8 | 2.7 | 1.2–5.3 | 16 |
| Radiation therapy and chemotherapy | 75 | 1.7 | 1.4–2.2 | 9 | 122 | 2.1 | 1.7–2.5 | 16 |
| Radiation fields b | ||||||||
| Breast (no IMC) | 87 | 1.2 | 0.9–1.4 | 2 | 81 | 0.8 | 0.6–1.0 | −3 |
| Chest wall (no IMC) | 34 | 1.5 | 1.0–2.0 | 14 | 42 | 1.0 | 0.7–1.3 | −1 |
| IMC | 203 | 1.9 | 1.6–2.1 | 23 | 205 | 1.2 | 1.0–1.4 | 6 |
| Chemotherapy regimens | ||||||||
| CMF-like regimens | 59 | 1.7 | 1.3–2.2 | 11 | 44 | 1.0 | 0.8–1.4 | 0 |
| Anthracycline-based regimensc | 22 | 1.5 | 0.9–2.2 | 3 | 86 | 4.6 | 3.7–5.7 | 33 |
| Cardiovascular risk factor at BC diagnosis d | ||||||||
| None known | 342 | 1.3 | 1.2–1.5 | 6 | 347 | 1.0 | 0.9–1.1 | −1 |
| At least one | 52 | 2.3 | 1.7–3.0 | 42 | 49 | 1.3 | 1.0–1.8 | 17 |
| Smoking | ||||||||
| Never | 110 | 1.1 | 0.9–1.3 | 3 | 115 | 0.8 | 0.6–0.9 | −10 |
| Currently or previous | 174 | 2.3 | 2.0–2.7 | 28 | 141 | 1.4 | 1.2–1.6 | 11 |
| Unknown | 110 | 1.0 | 0.8–1.2 | 0 | 140 | 0.9 | 0.8–1.1 | −1 |
SIR standardised incidence ratio, CI confidence interval, AER absolute excess risk, IMC internal mammary chain.
aExpected numbers were calculated using age-, sex- and calendar period-specific CVD incidence rates for the Dutch population. Myocardial infarction and heart failure incidence data from the Continuous Morbidity Registration Nijmegen of General Practices were used as reference rates for the years 1971–1999 and from the Netherlands Institute for Health Services Research Primary Care Database from 2000 onwards. Myocardial infarction included diagnoses I21–22 International Classification of Diseases, 10th revision. Heart failure included both cardiomyopathy and congestive heart failure; diagnoses I42 and I50 International Classification of Diseases, 10th revision. These were the only two cardiovascular diseases for which general population data were available. Just as in the general population registries, each individual patient in our cohort could have had a diagnosis of both myocardial infarction and heart failure.
bMutually exclusive treatment categories.
cIncluding either epirubicin or doxorubicin.
dHypertension, hypercholesterolaemia or diabetes mellitus