As treatments for breast cancer (BC) become more effective in prolonging survival, there is a greater chance that older women will die of other diseases, most commonly, heart disease. To help assess the extent of cardiovascular (CV) disease risk in older women (i.e., those aged over 65 years at the time of BC diagnosis), data surveillance from the Surveillance, Epidemiology, and End Results (SEER) cancer database from between 2004 and 2013 were analyzed. The national database contains insurance information for approximately 35% of the U.S. population, including those with Medicare Parts A and B who are aged 65 years and older and those under age 65 years who have specific disabilities.
This matched cohort study included all women aged 65 years and older with newly diagnosed BC identified between 2004 through 2013 who had 1 year of continuous Medicare Parts A and B coverage prior to the diagnosis. Women were matched according to year of birth, SEER U.S. region, and race/ethnicity. Women who were diagnosed with any other cancers beside nonmelanoma skin cancer were excluded if the malignancy occurred prior to the index date for the study.
The study’s main outcomes included the following CV conditions: coronary artery disease (CAD) (i.e., angina, myocardial infarction [MI], revascularization, sudden cardiac arrest), peripheral vascular disease (PVD), stroke, arrhythmia, heart failure (HF), pericarditis, valvular heart disease (VHD), and venous thromboembolism (VTE) (i.e., deep vein thrombosis [DVT], pulmonary embolism [PE]) as identified by ICD (International Classification of Diseases)-9 diagnostic and procedure codes and Healthcare Common Procedure Coding System procedure codes. The lookback period was 1 year prior to the BC diagnosis and was based on a modified Charlson comorbidity index. Both inpatient and outpatient claims were analyzed. In the case of outpatient claims, two claims had to be separated by >30 days.
Of the 545,670 women aged over 65 years who were enrolled in the study, 17% had BC. Hypertension and diabetes were slightly more prevalent in those with BC compared with those without BC, but other CV conditions were a bit lower in the former group. Mean follow-up varied from 3.73 years in those with VHD to 4.5 years in those with PE.
There was evidence of a slightly lower risk of angina (adjusted hazard ratio [HR] = 0.93, CI 0.91-0.95); MI (adjusted HR = 0.97, CI 0.94-1.0); revascularization (adjusted HR 0.89, CI 0.85-0.92); PVD (adjusted HR = 0.93, CI 0.91-0.94); and stroke (adjusted HR = 0.98, CI 0.97-1.00) in women with BC compared to those without the condition, although the MI and stroke differences were not statistically significant. However, there was also evidence showing an increase in risk of sudden cardiac arrest (adjusted HR = 1.05, CI 1.01-1.10); arrhythmias (adjusted 1.09, CI 1.07-1.10); HF (adjusted HR= 1.07, CI 1.06-1.09); pericarditis (adjusted HR 1.43, CI 1.38-1.49); VHD (adjusted HR = 1.09, CI 1.07-1.11); and DVT (adjusted HR = 1.67, CI 1.62-1.73) in the oncological group compared with controls.
Further analysis revealed that a BC diagnosis was associated with higher risk of CAD (adjusted HR = 1.08, CI 1.02-1.15); DVT (adjusted HR = 1.84, CI 1.65-2.05); and a trend toward increased risk of MI (adjusted HR = 1.10, CI 1.00-1.22) in black women. VTE (adjusted HR = 1.58, CI 1.52-1.64) and DVT (adjusted HR = 1.65, CI 1.59-1.71) were also increased in white women. Similar trends were seen in Asian (adjusted HR VTE = 1.49, CI 1.09-2.05 and adjusted HR DVT = 1.54, CI 1.09-2.18) and Hispanic women (adjusted HR VTE = 1.53, CI 1.05-2.24 and adjusted HR DVT = 1.62, CI 1.11-2.36).
Although information on BC treatments was available from claims data, this was not included in the analysis. Therefore, these numbers do not shed light on the cardiotoxic effects of chemotherapeutic agents.
Pharmacists caring for older women with BC should be cognizant of the increased risk of CV disease in this population. Pharmacists can utilize this knowledge to monitor older women, especially those on cardiotoxic medications, and to suggest referral to medical follow-up when deemed necessary.
The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.
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