Medication adherence mediates the relationship between marital status and cardiac event-free survival in patients with heart failure

ObjectivePrognosis is worse in unmarried patients compared with married patients with heart failure (HF). The reasons for differences in outcomes are unclear, but variations in medication adherence may play a role, because medication adherence is essential to achieving better outcomes. The study objective was to determine whether medication adherence mediated the relationship between marital status and cardiac event-free survival in patients with HF.MethodsDemographic, clinical, and psychosocial data were collected by questionnaires and medical record review for 136 patients with HF (aged 61 ± 11 years, 70% were male, 60% were in New York Heart Association class III/IV). Medication adherence was monitored objectively for 3 months using the Medication Event Monitoring System. Cardiac event-free survival data were obtained by patient/family interview, hospital database, and death certificate review. A series of regression and Cox survival analyses were performed to determine whether medication adherence mediated the relationship between marital status and event-free survival.ResultsCardiac event-free survival was worse in unmarried patients than in married patients. Unmarried patients were more likely to be nonadherent and 2 times more likely to experience an event than married patients (P = .017). Marital status was not a significant predictor of event-free survival after entering medication adherence in the model, demonstrating a mediation effect of adherence on the relationship of marital status to survival.ConclusionMedication adherence mediated the relationship between marital status and event-free survival. It is important to design interventions to increase medication adherence that take into account subgroups, such as unmarried patients, who are at higher risk for nonadherence.