Patterns of adjuvant hormonal therapy adherence and persistence among insured women with early breast cancer in Texas and the associated financial burden

Jung Hyun Kim, The University of Texas School of Public Health


Purpose: Overall objective of this study is to examine the geographical patterns of adjuvant hormonal therapy adherence and persistence and the associated factors in insured women aged 18-64 with early breast cancer in Texas as well as to understand an impact of financial burden on the adherence and persistence. Methods: We conducted a retrospective cohort study by using claims data for population insured by Blue Cross Blue Shield of Texas (BCBSTX) from the year 2008 to 2013. Women diagnosed with early breast cancer who were taking tamoxifen or aromatase inhibitors (AIs) for adjuvant hormonal therapy with at least one prescription claim, from January 1, 2008 to December, 31, 2012, and were enrolled through 2013, were identified. Outcomes include 1) adherence to adjuvant hormonal therapy, which was measured by Medication Possession Ratio (MPR). MPR was defined as the ratio of days covered by the amount of medication supplied, and women whose MPR is greater than or equal to 80%, were defined as adherent to the therapy; 2) persistence on adjuvant hormonal therapy, which is the duration of time from initiation to discontinuation of therapy. Women without a gap between two consecutive dispensed prescriptions of at least 90 days in medication were considered as persistently taking the medications. Patient-level multivariate logistic regression models with repeated regional-level adjustments were used to determine the geographical variations and patient-level, provider-level, and area-level factors that were associated with adjuvant hormonal therapy adherence. Cox proportional hazards model was conducted to assess time to the first 90+-day gap for persistence and a Kaplan-Meier curves were used to estimate probabilities to calculate the percentages of women who experienced 90+-day gaps in hormonal therapy. Results: Of the 938 women in the cohort, 627 (66.8%) initiated adjuvant hormonal therapy. Most of the smaller HRRs have significantly higher or lower rates of treatment adherence and persistence rates relative to the median regions. The use of AHT varies substantially from one geographical area to another, especially for adherence, with an approximately two-fold difference between the lowest and highest areas. Patient-level and area-level factors were found to be significantly associated with the compliance of AHT. By year one, 66.9% of women were adherent to the therapy, and by year five, 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: There are geographical variations in AHT adherence and persistence in Texas. Patient-level and area-level factors have significant associations explaining these patterns. Financial burdens including both non-AHT medication and AHT specific out-of-pocket costs were significantly associated with adherence and persistence to the therapy.^

Subject Area

Health sciences|Public health

Recommended Citation

Kim, Jung Hyun, "Patterns of adjuvant hormonal therapy adherence and persistence among insured women with early breast cancer in Texas and the associated financial burden" (2016). Texas Medical Center Dissertations (via ProQuest). AAI10249781.