Adjuvant hormonal therapy for early breast cancer: an epidemiologic study of medication adherence

The aim of this study was to determine the prevalence of adherence to adjuvant hormonal therapy (AHT) and to identify risk factors for medication non-adherence in clinical practice in patients with early-stage hormone receptor (HR)-positive breast cancer (BC) previously treated with chemotherapy.

We carried out a cross-sectional, observational, prospective, and multicenter survey based on a structured self-report postal questionnaire (35 items investigating six areas). A sample of 474 patients was drawn from 676 patients potentially eligible. The structured and validated Morisky Medication Adherence Scale-4 items was used for measuring medication adherence. An analysis of risk factors for non-adherence to AHT was performed using a two-step approach: univariate, then multivariate analysis.

A total of 280 patients out of the 428 analyzed patients participated in the survey, yielding a response rate of 65.4% [60.9-69.9]. The prevalence of adherence to AHT was estimated at 68.6% [63.1-74.0], corresponding to a high level of adherence. Three risk factors for non-adherence to AHT were identified: > 2 medications to treat comorbidities (p-value = 0.003), age less than 65 years (p-value = 0.008), and patient management in a university hospital setting (p-value = 0.014).

Non-adherence is a common, complex, and multidimensional healthcare problem. This better understanding and knowledge of risk factors will allow healthcare providers (such as oncologists, general practitioners, pharmacists) to more easily identify patients at risk for non-adherence and help them provide appropriate information about AHT and its management, thus improving medication adherence in their patients.