Prescription drug coverage: implications for hormonal therapy adherence in women diagnosed with breast cancer

In spite of its demonstrated benefits, many women do not initiate hormonal therapy, and among those who do, many discontinue it prematurely. We examined whether differences in hormonal therapy adherence may be at least partially explained by the availability of prescription drug coverage. Women aged 20–79 years diagnosed with stage I-III breast cancer between June 2005 and February 2007 were enrolled in the study. Women completed a mailed survey, on average 9 months after diagnosis, and again approximately 4 years later (N = 712). Adjusted logistic regression was used to predict the likelihood of initiating hormonal therapy and hormonal therapy continuation. Women who had prescription drug coverage were more likely to initiate hormonal therapy relative to women without prescription drug coverage (OR 2.91, 95 % CI 1.24–6.84). Women with prescription drug coverage were also more likely to continue hormonal therapy (OR 2.23; 95 % CI 0.99–5.05, p = 0.0543). The lowest income women were also less likely to continue hormonal therapy relative to women with annual household income that exceeded $70,000 (OR 0.55; 95 % CI 0.29–1.04) with a borderline significance of (p = 0.08). This study demonstrates the critical role of prescription drug coverage in hormonal therapy initiation and continuation, independent of health insurance coverage. These findings add to the body of literature that addresses medication adherence. Financial factors must be considered along with behavioral factors that influence adherence, which is becoming increasingly relevant to oncology as treatments are shifted to oral medications, many of which are very expensive.