Patient-Reported Outcomes and Long-Term Nonadherence to Aromatase Inhibitors

Abstract

Non-adherence to aromatase inhibitors (AIs) is common and increases risk of breast cancer (BC) recurrence. We analyzed factors associated with non-adherence among patients enrolled in S1105, a randomized trial of text-messaging. At enrollment, BC patients were required to have been on an adjuvant AI for ≥30 days and were asked about financial, medication and demographic factors. They completed Patient-Reported Outcomes (PROs) representing pain (Brief Pain Inventory), endocrine symptoms (FACT-Endocrine Symptoms), and beliefs about medications (Treatment Satisfaction Questionnaire for Medicine; Brief Medication Questionnaire). Our primary endpoint was AI non-adherence at 36 months, defined as urine AI metabolite assay p = .02). Fourteen baseline PRO scales were each statistically significantly associated with non-adherence. In a composite risk model categorized into quartile levels, each increase in risk level was associated with a 46.5% increase in the odds of non-adherence (OR = 1.47,95% CI = 1.26–1.70, p < .001). The highest risk patients were more than three times more likely to be non-adherent than the lowest risk patients (OR = 3.14, 95% CI = 1.97–5.02, p < .001). The presence of multiple baseline PRO-specified risk factors was statistically significantly associated with AI non-adherence. The use of these assessments can help identify patients for targeted interventions to improve adherence.