The mediation effect of health literacy between subjective social status and depressive symptoms in patients with heart failure.

OBJECTIVES: Depressive symptoms are prevalent and cause adverse outcomes in heart failure. Previous studies have linked depressive symptoms with socioeconomic status. However, little is known about the mechanisms underlying this relationship. This study aimed to evaluate the association between socioeconomic status and depressive symptoms, and to examine whether access to healthcare, health literacy and social support mediated this relationship in patients with heart failure.

METHODS: Cross-sectional design was used to study 321 patients with heart failure recruited from a general hospital. Demographics, clinical data, depressive symptoms, socioeconomic status (i.e., education, employment, income, and subjective social status), access to healthcare, health literacy, and social support were collected by patient interview, medical record review or questionnaires. A series of logistic regressions and linear regressions were conducted to examine mediation.

RESULTS: The mean age of patients with heart failure was 63.6±10.6years. Fifty-eight patients (18%) had depressive symptoms. Lower subjective social status (OR=1.321, p=0.012) and lower health literacy (OR=1.065, p<0.001) were separately associated with depressive symptoms. When subjective social status and health literacy were entered simultaneously, the relationship between subjective social status and depressive symptoms became non-significant (OR=1.208, p=0.113), demonstrating mediation. Additionally, lower social support was associated with depressive symptoms (OR=1.062, p=0.007).

CONCLUSIONS: In patients with heart failure, health literacy mediated the relationship between subjective social status and depressive symptoms. Lower social support was associated with depressive symptoms. Interventions should take these factors into account.