Fig. 3: Conceptual model illustrating the moderated mediation of depression and social networks in the frailty–quality of life relationship.

The diagram represents the hypothesized moderated mediation model. Frailty (X) is associated with depression (M), which in turn is related to quality of life (Y). Social network (W) moderates the path between depression and quality of life. Paths a, b, and c’ denote the direct and indirect effects tested in the model.