Abstract 2510: Nonadherence is a Mediator of the Link Between Depressive Symptoms, and Rehospitalization or Mortality in Patients with Heart Failure
The mechanisms linking depression with poor outcomes in heart failure (HF) are unknown. Although depression is known to affect adherence, few have examined behavioral mediators of the link between depression and HF outcomes. Purpose: To determine whether nonadherence mediated any association between depression and outcomes.
Methods: We followed 111 HF patients (age 61 ± 11 yrs; 34% female; 66% NYHA class III/IV) for 6 months to determine rehospitalization and mortality rates. At baseline, depression was measured using the Patient Health Questionnaire-9. Adherence was measured objectively by Medication Event Monitoring System (MEMs) and 24-hour urinary sodium excretion (UNA); and subjectively by Medical Outcomes Study Adherence Scale (MOS). Survival and multiple regression mediation analyses tested the hypothesis that nonadherence mediates the link between depression and outcomes.
Results: Presence of depressive symptoms independently predicted rehospitalization/mortality (OR 1.2, p = .003). Patients with depressive symptoms were less adherent than non-depressed patients to medication-taking behavior (figure⇓), and to activity, smoking, alcohol intake, medication taking, daily weighing and symptom monitoring (each p<0.05) assessed by MOS. There was no association between depression and dietary sodium adherence (UNA). Mediation analysis indicated nonadherence (MEMS and MOS) mediated the relationship between depression and rehospitalization/mortality.
Conclusions: An important mechanism linking depression and HF outcomes is nonadherence to the prescribed regimen. Interventions to reduce depression will enhance adherence and improve HF outcomes.