Medication adherence, depressive symptoms, and cardiac event-free survival in patients with heart failure

Background: Medication nonadherence and depressive symptoms predict hospitalization and death in patients with heart failure (HF). Depressed patients have lower medication adherence than nondepressed patients. However, the predictive power of the combination of medication adherence and depressive symptoms for hospitalization and death has not been investigated in patients with HF. Objective: The aim of this study was to explore the combined influence of medication adherence and depressive symptoms for prediction of cardiac event-free survival in patients with HF. Methods and Results: We monitored medication adherence in 216 HF patients who completed the Patient Health Questionnaire-9 (PHQ-9) at baseline. Medication adherence was measured objectively with the use of the Medication Event Monitoring System (MEMS). Patients were followed for up to 3.5 years to collect data on cardiac events. Survival analyses were used to compare cardiac event-free survival among groups. The risk of experiencing a cardiac event for patients with medication nonadherence and depressive symptoms was 5 times higher than those who were medication adherent without depressive symptoms. The risk of experiencing a cardiac event for patients with only 1 risk factor was 1.2-1.3 times that of those with neither risk factor. Conclusions: Medication nonadherence and depressive symptoms had a negative synergistic effect on cardiac event-free survival in patients with HF.