Table 2.

Use of antihypertensive medications and risk of second primary CBC

ControlsCases
n = 661n = 352
Use of antihypertensive medicationsn (%)n (%)OR (95% CI)
Use of calcium channel blockers
 Never557 (84.0)295 (84.0)Reference
 Ever (≥6 mo)85 (13.0)47 (13.4)1.1 (0.7–1.6)
 Unknowna01NA
Recency of use among ever usersb
 Former15 (2.4)10 (3.0)1.4 (0.6–3.5)
 Current60 (9.5)33 (9.8)1.1 (0.7–1.7)
Duration of use among current users
<2 y17 (2.8)10 (3.0)1.1 (0.5–2.6)
 2–3 y15 (2.4)3 (0.9)0.3 (0.1–1.6)
 ≥3 y28 (4.5)20 (6.1)1.4 (0.7–2.6)
Use of β-blockers
 Never535 (81.0)289 (82.3)Reference
 Ever (≥6 mo)97 (15.0)54 (15.4)1.0 (0.7–1.4)
 Unknowna21NA
Recency of use among ever users
 Former14 (2.2)7 (2.1)1.2 (0.4–3.2)
 Current75 (12.0)41 (12.2)1.0 (0.6–1.5)
Duration of use among current users
 <2 y20 (3.3)9 (2.7)0.8 (0.3–1.9)
 2–3 y12 (2.0)8 (2.4)1.3 (0.5–3.3)
 ≥3 y43 (7.0)24 (7.3)0.9 (0.5–1.6)
Use of ACE inhibitors
 Never522 (79.0)271 (77.2)Reference
 Ever (≥6 mo)114 (17.0)72 (20.5)1.2 (0.9–1.8)
 Unknowna11
Recency of use among ever users
 Former20 (3.2)11 (3.3)1.0 (0.4–2.4)
 Current80 (13.0)54 (16.1)1.3 (0.8–2.0)
Duration of use among current users
 <2 y31 (5.1)21 (6.5)1.2 (0.6–2.3)
 2–3 y13 (2.2)11 (3.4)1.7 (0.7–4.1)
 ≥3 y36 (6.0)22 (6.8)1.1 (0.6–2.1)
Use of diuretics
 Never449 (68.0)238 (68.4)Reference
 Ever (≥6 mo)177 (27.0)96 (27.6)1.0 (0.7–1.4)
 Unknowna44
Recency of use among ever users
 Former31 (5.2)15 (4.6)1.0 (0.5–2.1)
 Current119 (20.0)72 (22.2)1.2 (0.8–1.7)
Duration of use among current users
 <2 y35 (6.2)29 (9.4)1.6 (0.9–2.8)
 2–3 y20 (3.5)11 (3.5)1.2 (0.5–3.0)
 ≥3 y64 (11.0)32 (10.3)1.0 (0.6–1.7)

NOTE: ORs and 95% CIs were estimated using conditional logistic regression to account for matching factors (age, year of first breast cancer diagnosis, stage of risk breast cancer, county of residence, and race/ethnicity). All models were additionally adjusted for receipt of adjuvant hormone therapy, radiation therapy, and chemotherapy.

  • aTo maximize the use of data, patients who used multiple drugs of a same class and had missing duration of use for some of these drugs were classified as ever users if known duration of use was ≥6 months or unknown users if known duration of use was <6 months.

  • bPatients who had any incomplete information on duration of use were dropped from analyses on recency and duration.