Perceived social support predicted quality of life in patients with heart failure, but the effect is mediated by depressive symptoms

Depressive symptoms and inadequate social support are well-known independent predictors of increased mortality and morbidity in heart failure (HF). However, it is unclear how depressive symptoms and social support interact to influence quality of life. Thus, the purpose of this study was to determine the nature of the relationships (direct, mediator, and moderator) among depressive symptoms, social support, and quality of life in patients with HF. We performed a secondary data analysis that included 362 patients with HF who completed the measures of depressive symptoms (the Beck Depression Inventory-II), perceived social support (the Multidimensional Scale of Perceived Social Support), and quality of life (the Minnesota Living with Heart Failure Questionnaire) instruments. The direct, mediator, and moderator effects of both depressive symptoms and social support on quality of life were tested using multiple regressions and 2 x 2 ANCOVA. Less social support and greater depressive symptoms independently predicted poorer quality of life. The relationship between social support and quality of life was mediated by depressive symptoms. Neither social support nor depressive symptoms moderated quality of life. Promotion of social support will improve quality of life only when depressive symptoms are also effectively managed.