Background Adherence to oral endocrine therapy (OET) is crucial in ensuring its maximum benefit in prevention and treatment of hormone receptor-positive (HR+) breast cancer (BC) in patients. Medication use behavior is suboptimal especially in racial/ethnic minorities of lower socioeconomic status (SES). We aimed to assess the OET adherence and its predictors in racial/ethnic minority patients of lower SES. Aim We aimed to assess the OET adherence and determine the predictors of OET nonadherence in racial/ethnic minority patients of lower SES. Method A retrospective study was conducted at the Harris Health System in Houston, Texas. Since the study period included the COVID-19 pandemic, data was collected during the 6 months prior and 6 months after the start of the pandemic. The adherence was assessed using the prescription refill data using the proportion of days covered. Multivariable logistic regression model was used to identify predictors of nonadherence. Eighteen years or older patients on appropriate doses of OET for prevention or treatment of BC were included. Result In 258 patients, the adherence was significantly lower during the pandemic (44%) compared to before the pandemic (57%). The predictors of OET nonadherence before the pandemic were Black/African American, obesity/extreme obesity, prevention setting, tamoxifen therapy, and 4 or more years on OET. During the pandemic, prevention setting and those not using home delivery were more likely to be nonadherent. Conclusion Racial/ethnic minority patients of lower SES, especially African Americans and those using OET for prevention of BC, require individualized interventions to improve adherence.

Introduction: Medication adherence is important in ensuring the maximum effect of oral endocrine therapy (OET) in hormone receptor-positive breast cancer (HR+ BC) patients. Low medication adherence is more seen in racial and ethnic minority patients of lower socioeconomic status. COVID-19 pandemic has further introduced complexities that have impacted patients’ medication-use behaviors. Our goal was to (1) assess the medication adherence to OET in racial and ethnic minority patients of lower socioeconomic status with HR+ BC and (2) assess the impact of the COVID-19 pandemic on their OET adherence. Patients and Methods: A retrospective, single-center study from September 2019 through September 2020 was conducted. The primary endpoint was adherence rate during the 6 months prior (September 2019 - February 2020) and 6 months after (April 2020 - September 2020) the COVID-19 pandemic started in the United States. The following three racial/ethnic groups were compared: Non-Hispanic White/Caucasian, Black/African American, and Hispanic/Latino. Chi-Square and Student’s t-tests were used to compare the adherent and nonadherent groups. The secondary endpoint was to identify predictors of nonadherence to OET. Multivariable logistic regression model was used to assess predictors of nonadherence. Results: Out of 270 patients, a total of 251 patients had a refill for an OET before COVID-19 with a mean proportion of days covered (PDC) of 0.72%. Of these, 140 (55.78%) were adherent and 111 (44.22%) were nonadherent. A total of 194 patients had a refill for an OET during COVID-19 with a mean PDC of 0.67%. Of these, 83 (42.78%) were adherent and 111 (57.22%) were nonadherent. A total of 187 patients had a refill for OET before and during the COVID-19 pandemic. There was a significant difference in the adherence before and during the pandemic when PDC was used as a continuous (p <0.0001, Student’s paired t-test) or a categorical variable (p <0.0001, McNemar chi-square test). In a multivariate analysis of data before the pandemic, Black/African American and White/Caucasian were less likely to be adherent compared to Hispanic/Latino (Black/African American: odds ratio [OR], 0.36; 95% confidence interval [CI], 0.18-0.723; White/Caucasian: OR, 0.25; 95% CI, 0.074-0.853). Patients with diabetes mellitus (DM) were more likely to be adherent compared to patients without DM (OR, 2.364; 95% CI, 1.199-4.662), and patients with hypertension (HTN) were less likely to be adherent compared to patients without HTN (OR, 0.481; 95% CI, 0.236-0.981). Patients who were prescribed aromatase inhibitors were more likely to be adherent compared to patients that were prescribed tamoxifen (OR, 0.484; 95% CI, 0.235-0.998). Patients diagnosed with invasive BC (stages 1-4) were more likely to be adherent compared to those diagnosed with non-invasive (in situ) tumors or ductal/lobular hyperplasia. During the pandemic, patients who used home delivery were more likely to be adherent compared to those who did not use home delivery (OR, 11.574; 95% CI, 2.45-54.55). There was no significant difference in the proportion of patients using home delivery between different racial and ethnic groups. Conclusion: OET adherence was reduced during the COVID-19 pandemic in racial and ethnic minority patients with low socioeconomic status. Tamoxifen therapy, Black/African American, and White/Caucasian origin, not having DM, having HTN, and diagnosed with non-invasive BC were associated with OET nonadherence in patients before the COVID-19 pandemic. Whereas, not using home delivery for OET medications predicted nonadherence in patients during the COVID-19 pandemic. Citation Format: Sama Rahimi, Onyebuchi Ononogbu, Anjana Mohan, Daniel Moussa, Susan Abughosh, Meghana V Trivedi. Predictors of adherence to oral endocrine therapy in racial and ethnic minority patients with low socioeconomic status before and during the COVID-19 pandemic [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-14-06.

Background Adherence to oral endocrine therapy (OET) is crucial in ensuring its maximum benefit in the prevention and treatment of hormone receptor-positive (HR +) breast cancer (BC). Medication use behavior is suboptimal especially in racial/ethnic minorities with lower socioeconomic status (SES). Aim We aimed to assess the impact of the coronavirus disease 2019 (COVID-19) pandemic on OET adherence and identify demographic and/or clinical characteristics associated with nonadherence in racial/ethnic minorities with lower SES. Method A retrospective study was conducted at the Harris Health System in Houston, Texas. Data were collected during the 6 months before and 6 months after the start of the pandemic. The adherence was assessed using the prescription refill data using the proportion of days covered. A multivariable logistic regression model was used to identify demographic/clinical characteristics associated with nonadherence. Eighteen years or older patients on appropriate doses of OET for prevention or treatment of BC were included. Results In 258 patients, adherence was significantly lower during the pandemic (44%) compared to before the pandemic (57%). The demographic/clinical characteristics associated with OET nonadherence before the pandemic were Black/African American, obesity/extreme obesity, prevention setting, tamoxifen therapy, and 4 or more years on OET. During the pandemic, prevention setting and those not using home delivery were more likely to be nonadherent. Conclusion OET adherence was significantly reduced during the COVID-19 pandemic in racial/ethnic minority patients with low SES. Patient-centered interventions are necessary to improve OET adherence in these patients.