Mediators of the Effect of an Educational Intervention on Health-Related Quality of Life in Patients With Heart Failure: A Causal Mediation Analysis.

BACKGROUND: Although nursing interventions improve outcomes in heart failure (HF), the mechanisms underlying their effects on health-related quality of life (HRQOL) remain unclear. OBJECTIVE: Using a causal mediation framework, we examined whether HF knowledge, self-care behaviors, self-care confidence, or social support mediated the effect of an educational intervention on HRQOL in patients with HF. METHODS: We analyzed data from a randomized controlled trial of an educational intervention for patients with HF. The intervention group (n = 60; 64.61 ± 13.75 years; 50.0% female) received individual education plus 8 weeks of telephone follow-up, while the control group (n = 62; 67.89 ± 13.31 years; 51.7% female) received usual care. Causal mediation analysis was used to explore the pathway between intervention assignment and HRQOL at 6 months, with HF knowledge, self-care behaviors (ie, overall self-care, self-care management, and self-care maintenance), self-care confidence, and social support measured at 3 months as potential mediators. RESULTS: Intervention assignment was significantly associated with HF knowledge, overall self-care, self-care maintenance, self-care management, and self-care confidence at 3 months (all P < .05). After adjusting for age, gender, and baseline scores, overall self-care (indirect effect -7.18, 95% CI -13.48 to -2.35) and self-care maintenance (indirect effect -3.02, 95% CI -7.94 to -0.07) demonstrated significant indirect effects. Overall self-care and self-care maintenance also had significant indirect effects between intervention and physical HRQOL, but no mediator was significant for emotional HRQOL. CONCLUSIONS: Educational interventions can improve HRQOL of patients with HF by enhancing their self-care, particularly treatment adherence and self-monitoring. However, additional strategies are needed for emotional HRQOL.