PhD Candidate Department of Practice, Sciences, and Health Outcomes Research, University of Maryland School of Pharmacy, Baltimore, USA Baltimore, United States
Background: Hypertension is the most prevalent comorbidity in cancer and may increase the risk for cancer treatment-induced cardiomyopathy when not properly controlled. Evidence from RCTs suggests that Angiotensin Converting Enzyme Inhibitors (ACEIs), Angiotensin Receptor Blockers (ARBs) and Beta-Blockers (BB) are cardioprotective when used in cancer survivors. Among individuals with pre-existing hypertension, it is unknown whether after cancer treatment initiation, adherence to antihypertensives considered highly cardioprotective is increased compared to medium or low cardioprotective classes.
Objectives: To examine whether adherence to antihypertensive treatment is higher among cancer survivors treated with high (ACEIs, ARBs, and BB) compared to moderate (Calcium Channel Blockers (CCB)) or low (Diuretics) cardioprotective antihypertensive classes.
Methods: This retrospective cohort study utilized the 10% random sample of enrollees within IQVIA PharMetrics® Plus for Academics database from January 1, 2006, and December 31, 2021. We identified individuals 18 to 64 years old, with a hypertension diagnosis, initiating cancer treatment (including surgery, chemotherapy, hormonal therapy, or radiotherapy), with a cancer diagnosis claim for thyroid, breast, melanoma of the skin, Non-Hodgkin’s, and Hodgkin’s lymphomas within 90 days of the treatment initiation date. Cancer treatment initiation date was the index date. Survivors were required to have continuous enrollment one year before and after the index date. Adherence to antihypertensives was measured in the 12 months after the index date using proportion of days covered (PDC). PDC was defined as adherent (≥80%) or nonadherent ( < 80%). Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for adherence to antihypertensives, comparing the high and moderate to the low cardioprotective class. We adjusted for cancer type and cancer treatment modality, age, sex, payment type, and metastatic cancer status.
Results: We identified 1109 individuals with pre-existing antihypertensive use, and 57% had a breast cancer diagnosis. The overall mean age was 56 years. In the high group, 71% were adherent compared to 74% in the moderate and 63% in the low cardioprotective group (p-value: 0.07). After adjusting for potential confounders, the high group (OR:1.48, 95% CI: 1.03-2.12) and moderate group (OR: 1.72, 95% C.I: 0.96-3.00) had higher odds of adherence when compared to low group.
Conclusions: Non-adherence in the low cardioprotective group may be secondary to changes in antihypertensive treatment. Further research is needed to explore the rate of such changes and impact on cardiovascular outcomes during early cancer treatment.
