Association between financial burden and adjuvant hormonal therapy adherence and persistent use for privately insured women aged 18–64 years in BCBS of Texas

Purpose: The objective of this study is to understand an impact of financial burden on the adjuvant hormonal therapy (AHT) adherence and persistence for insured women aged 18–64 with early breast cancer in Texas. Methods: We conducted a retrospective cohort study using claims data for population insured by Blue Cross Blue Shield of Texas from the year 2008 to 2013. Outcomes include adherence to adjuvant hormonal therapy, which was measured by medication possession ratio and persistence on AHT, which is the duration of time from initiation to discontinuation of therapy. Multivariate logistic regression models with repeated regional-level adjustments were used to explore the odds of AHT adherence. Cox proportional hazards model was conducted to assess time to the first 90+-day gap for persistence and a Kaplan–Meier curve were used to estimate probabilities to calculate the percentages of women who experienced 90+-day gaps in AHT. Results: Of the 938 women in the cohort, 627 (66.8%) initiated the treatment. By year 1, 66.9% of women were adherent to the therapy, and by year 5, only 29% of those were adherent. The percentage of women with no gap in therapy greater than 90 days was 80.8%. Both higher out-of-pocket costs spent on all prescription drugs except AHT and AHT-specific out-of-pocket costs were negatively associated with adherence to AHT as well as continuing AHT as recommended. Conclusions: Financial burdens including both non-AHT medication and AHT-specific out-of-pocket costs were significantly associated with adherence and persistence to the therapy.