Purpose: 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.
Methods: A retrospective cohort study was conducted 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. Adherence to adjuvant hormonal therapy and persistence on adjuvant hormonal therapy were calculated as outcome measures. 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.
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 and area-level factors were found to be significantly associated with the compliance of AHT.
Conclusions: There are geographical variations in AHT adherence and persistence in Texas. Patient-level and area-level factors have significant associations explaining these patterns.