Antihypertensive Past Adherence Trajectories and Risk of Cardiotoxicity Among Adults Initiating Anthracycline Treatment.

BACKGROUND

Poor blood pressure control and low adherence to antihypertensives increase the risk for anthracycline-induced cardiotoxicity (AIC) in hypertensive cancer patients. Little is known about whether past adherence to antihypertensive medications can reduce the risk of AIC in patients initiating anthracyclines. We examined adherence to antihypertensives pre-anthracycline initiation and its association with the risk of AIC.

METHODS

We conducted a retrospective cohort study using a 25% random sample of IQVIA PharMetrics Plus for Academics US health plan claims, 2006-2022. We identified individuals 18- 64 years old, with hypertension, diagnosed with breast cancer or lymphoma (Hodgkin's or Non-Hodgkin's) 9 months before the anthracycline treatment initiation (index date). Group-based trajectory modeling was used to estimate latent subgroups of antihypertensive adherence before the index date, using monthly proportions of days covered over the 9 months (baseline). Using Cox regression models, we examined the risk of AIC in the 12 months after the index date.

RESULTS

We identified four distinct antihypertensive adherence trajectory groups in the baseline period. In the adjusted model, the risk of AIC was higher in the early decline group (hazard ratio [HR] = 1.67, 95% CI [1.11-2.49]) and the moderate adherence (HR = 1.62, 95% CI [1.16-2.26]) groups compared to the near-perfect adherence group. Comorbidities associated with an increased risk of AIC include diabetes and chronic kidney failure.

CONCLUSION

Poor adherence to antihypertensives prior to anthracycline use was associated with AIC. Future studies should explore whether select antihypertensive classes are more cardioprotective than others.