Abstract A34: Differences between self-reported and electronically monitored adherence among Korean breast cancer patients receiving endocrine therapy

Abstract

Abstract Background: The aim of this study was to compare self-report medication adherence measure with adherence data collected from Medication Event Monitoring System (MEMS) electronic monitors in Korean breast cancer survivors. Methods: Between June 2017 and January 2018, patients who planned to take endocrine therapy (ET) were recruited for this observational cohort study. Adherence was assessed by participants’ self-reports at 3 different time points and by MEMS for the first 12 months of ET. The time points 1, 2, and 3 were at approximately 3 months, 6 months, and 12 months after initiation of ET. MEMS data that had the date and time of each pill bottle opening were used to calculate electronically monitored adherence (MEMS adherence). Self-reported and MEMS adherence measures were matched and compared for 146 patients. Results: The mean [±SD, interquartile range (IQR)] self-reported adherence and MEMS adherence were 95% (±11, 95-100%) and 84% (±16, 80-95%), respectively. The mean (±SD) difference between the self-reported adherence and the MEMS adherence was 11% (±13). Among those who self-reported no missed doses (self-reported adherence 100%) for 3 or 6 months, mean MEMS adherence and the proportion with MEMS adherence >90% (good adherence) were 89% and 64%, respectively. In comparison, among those who self-reported adherence 97-99%, 93-96%, 90-92%, and <90%, mean MEMS adherence was 86%, 83%, 79%, and 56% respectively, and the proportion with MEMS adherence >90% was 35%, 36%, 17%, and 0%, respectively. The difference between the two adherence measures increased over time. The differences at the time points 1, 2, and 3 was 9%, 11% and 17%, respectively. There was a strong relationship between the two adherence measures (r=0.59, p<0.001). Conclusions: There is a sizable and significant difference between self-reported and MEMS adherence. However, self-reported adherence correlated by MEMS adherence suggests that self-reported adherence gives a useful measure for clinical monitoring. This work was supported by the National Research Foundation of Korea grant funded by the Korea government (No. 2018R1A1A3A04076879). Citation Format: Yul Ha Min, Sae Byul Lee, Minsun Lee. Differences between self-reported and electronically monitored adherence among Korean breast cancer patients receiving endocrine therapy [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr A34.