Adherence to Adjuvant Endocrine Therapy in Insured Black and White Breast Cancer Survivors: Exploring Adherence Measures in Patient Data

Abstract

Purpose: The purpose of the study was to fill scientific gaps about predictors of adherence to adjuvant endocrine therapy (AET) among Black and White women diagnosed with breast cancer (BC). AET is a critical therapy in that it improves survival in women with hormone receptor positive (HR+) BC but adherence to AET is suboptimal. Objective: To assess AET adherence in Black and White insured women using multiple measures, including one that uses an innovative statistical approach. Methods: Black and White women newly diagnosed with HR+ BC were identified from two health maintenance organizations. Pharmacy records captured the type of oral AET prescriptions and all fill dates. Multivariable logistic regression was used to identify predictors of adherence defined in terms of proportion of days covered (PDC) (≥80%) and medication gap of ≤10 days. A zero-inflated negative binomial (ZINB) regression model was used to identify variables associated with the total number of days of medication gaps. Results: A total of 1,925 women met inclusion criteria. Eighty percent of women were PDC –adherent (>80%); 44% had a medication gap of ≤10 days; and 24% of women had zero days without any medication gaps. Race and age were significant in all multivariable models. Black women were less likely to be adherent based on PDC than Whites (OR=0.72; 95%CI: 0.57–0.90; p<0.01), and they were less likely to have a medication gap of ≤10 days (OR=0.65; 95%CI: 0.54–0.79; p<0.01). Women 25–49 years old were less likely to be PDC adherent than women 65–93 years old (OR=0.65; 95%CI: 0.48–0.87; p<0.001). In the zero-inflated negative binomial model, women were without their medication for an average of 37 days (SD=50.5). Conclusions: Racial disparities in adherence to AET in the study highlight a need for interventions among insured women. Using various measures of adherence may help to understand various components of this multidimensional concept. Thus, there might be benefits from using both more common dichotomous measures (e.g., PDC) and also integrating novel statistical approaches to allow one to tailor adherence to patterns within a specific sample.

Race and Patient-reported Symptoms in Adherence to Adjuvant Endocrine Therapy: A Report from the Women's Hormonal Initiation and Persistence Study

“…Though not always consistent across studies, reports suggest that African American (Black) women, are more likely to be non-adherent than their Non-Hispanic White (White) counterparts. [17][18][19] Suboptimal AET adherence in Black women is characterized by lower rates of treatment initiation, greater delays to initiate therapy after prescription (implementation), and failure to complete the full course of therapy (persistence). 20,21 However, little is known about Black women's adherence to their treatment regimens; particularly early in their treatment experience or whether if accounting for medication (i.e., symptom burden) and psychosocial factors such as medication beliefs would diminish some of the previously observed disparities.…”

The Impact of the COVID-19 Pandemic on Cancer Care and Health-Related Quality of Life of Non-Hispanic Black/African American, Hispanic/Latina and Non-Hispanic White Women Diagnosed with Breast Cancer in the U.S.: A Mixed-Methods Study Protocol

“…Traditional explanations have included biologic differences in tumor characteristics [ 81 ], late-stage diagnosis due to lack of cancer screening [ 91 , 92 , 93 ], and socioeconomic factors [ 83 , 94 ]. However, a growing body of literature suggests that differences in selection and adherence to recommended treatments may play a major role in the maintenance of disparities in breast cancer outcomes [ 83 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 ]. In the current oncologic practice, where timely engagement with treatment is crucial to prevent recurrence and reduce mortality [ 89 , 90 ], differences in treatment initiation and adherence to treatment have become increasingly relevant given the present recommendations for triage and modified delivery of cancer care [ 75 , 95 , 96 , 97 , 98 , 99 ].…”

“…Black/African American women are four times more likely to experience treatment delays and less likely to receive cancer-directed surgery; additionally, Black/African American and Hispanic/Latina women also fail to receive definitive local therapy, chemotherapy, and radiotherapy [ 99 , 100 , 101 ]. Minority breast cancer patients are disproportionally characterized by non-initiation, discontinuation, and non-adherence to adjuvant endocrine therapy [ 98 , 99 , 100 , 101 , 102 , 103 , 104 ], which leads to lower survival, shorter time to recurrence, increased medical costs, and lower quality of life [ 87 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 ]. Key determinants of disparities range from proximal factors (socio-demographic variables), to intermediate (social network characteristics), and distal factors (access to resources; healthcare system characteristics, and policy) [ 88 , 89 , 90 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 ].…”

Receipt of guideline‐concordant care among young adult women with breast cancer

“…In a study of the impact of GDC on survival in nonmetastatic breast cancer, women younger than 50 years (vs those older than 50 years) had higher odds of not having received recommended surgical or endocrine therapy 25 . A different study of insured women with HR+ breast cancer found that younger women (vs older women) were less likely to adhere to adjuvant endocrine therapy 26 . Potential explanations for treatment refusal may include the desire to avoid the negative effects of treatment on fertility, physical appearance, work/school schedule, and finances 27 …”

“…25 A different study of insured women with HR+ breast cancer found that younger women (vs older women) were less likely to adhere to adjuvant endocrine therapy. 26 Potential explanations for treatment refusal may include the desire to avoid the negative effects of treatment on fertility, physical appearance, work/school schedule, and finances. 27 A study of cancer registries (2004-2013) found that 58.1% of women aged 20 to 49 years had HR+/ HER2− tumors.…”