Evaluating the quality of real-world data on adherence to oral endocrine therapy in breast cancer patients: How real-world data?

Abstract

Simple Summary: The objective of this study was to evaluate the validity of RWD-based adherence measurements obtained from accessible electronic health records in the Spanish national health system in all women diagnosed with breast cancer in the public healthcare system in Catalonia (Spain). Our results showed that nonadherence during the first year of treatment was around 11% in both cohorts, analysed using the RWD, and without significant differences between them. Furthermore, determinants associated with nonadherence (age and type of oral endocrine treatment) were similar in both approaches used. The results also show that it is fast and feasible to use RWD to identify individuals who are not refilling prescriptions as often as they should. In conclusion, the validity of the RWD method to estimate adherence has been confirmed and, at the same time, this method provides valuable evidence to help oncologists discuss adherence with their patients.