Racial differences in long-term adjuvant endocrine therapy adherence and mortality among Medicaid-insured breast cancer patients in Texas: Findings from TCR-Medicaid linked data

Abstract

BackgroundThere are racial/ethnic disparities in breast cancer mortality may be attributed to differences in receipt of adjuvant cancer treatment. Our purpose was to determine whether the mortality disparities could be explained by racial/ethnic differences in long-term adherence to adjuvant endocrine therapy (AET).MethodsWe conducted a retrospective cohort study with the Texas Cancer Registry and Medicaid claims-linked dataset of women (20-64 years) diagnosed with local and regional breast cancer who filled a prescription for AET from 2000-2008. Adherence to AET was measured at three time points (1-, 3-, and 5-year adherence) using a value for the percentage of medication filled for each period divided by the total number of possible prescriptions prescribed (Medication Possession Ratio, MPR). We created a binary variable of adherence (MPR≥80%). We performed multivariable logistic regressions to assess racial differences for the odds of AET adherence and Cox proportional hazard models to determine the risk of mortality adjusting for potential confounding variables of SES, comorbidities, tumor prognostic factors, and other cancer treatment.ResultsOf the 1,497 women with breast cancer who initiated AET, 56.9%, 42.3%, and 33.3% were adherent for 1, 3, and 5-years, respectively. Hispanics compared to non-Hispanic whites did differ in the proportion that were adherent to 5-years of AET. In the adjusted analysis for long-term adherence to AET, Hispanics did not have a significantly increased risk of death compared to non-Hispanic white patients (HR: 1.13, 95% CI: 0.58-2.21). However, black compared to non-Hispanic white patients had significantly lower odds of three-year adherence (OR: 0.45, 95% CI: 0.28-0.73). After controlling for 5-year adherence to AET, the risk of death for black compared to non-Hispanic white patients was 12% lower (HR: 1.90; 95% CI: 1.03-3.51) and in the fully adjusted model, the disparity was reduced and no longer significant (OR: 1.86, 95% CI: 0.94-3.66).ConclusionsLong-term adherence in the Medicaid population is suboptimal and racial/ethnic differences in AET adherence may partially explain disparities in mortality. This study underscores the critical need to ensure long-term adherence to AET for all racial/ethnic groups to decrease disparities in mortality.

Factors influencing five-year adherence to adjuvant endocrine therapy in breast cancer patients: A systematic review

“… TAM & AI. N = 19551 Implementation PDC≥ 80% Year 1: 76.4%, Year 2: 72.1%, Year 3: 68.4%, Year 4: 65.7%, Year 5: 58.5% 1) Asian/Pacific Islander ethnic groups 1) Hispanic 2) Black Farias, 2018 (US) [ 41 ] Retrospective cohort. Regional Cancer Registry and Medicaid claims database.…”

“…The completeness and reliability of data source for 15 studies were considered to be good, with multiple databases linked together at national or regional level. Studies that used databases from private insurance or healthcare systems [ 34 , 40 , 41 , 46 , 47 ] and hospital or pharmacy databases without linkage to other databases [ 30 , 38 , 42 ] were rated as intermediate quality. One study was considered to have poor data source, as information was based on survey and incomplete data collection from medical charts [ 27 ].…”

Impact of deviation from guideline recommended treatment on breast cancer survival in Asia

“…Endocrine therapy is typically recommended for at least five years. While we were not able to study drug adherence in our patients, unsatisfactory adherence to treatment for the entire recommended duration is known to be associated with worse survival, which could potentially explain the observed increasing mortality rate among treatment-compliant patients in our study 28 . As such, the survival benefit of endocrine therapy compliance would better reach its full potential if common factors contributing to non-adherence, such as patient forgetfulness and concerns about adverse effects, were followed up and addressed 29 .…”

Cancer stem cells: Culprits in endocrine resistance and racial disparities in breast cancer outcomes

“…Racial differences have been found in the adherence to adjuvant ET to impact survival among breast cancer patients [105] (Table 2). Some found that the racial disparity in luminal breast cancer survival is unrelated to differences in tumor stage or therapy initiation but rather to differences in tumor biology that may render them less responsive to ET [9].…”