Mediating medication adherence in renal transplant recipients: the roles of depressive symptoms and cognition

Cognitive abilities and depressive symptoms have been previously linked to medication adherence following renal transplantation. To further elucidate these relationships, we assessed two potential mediational models: 1) depressive symptoms mediate the relationship between cognition and adherence; and 2) cognition mediates the relationship between depressive symptoms and adherence. Renal transplant recipients (N=101) completed a cognitive battery, the CES-D, and the Transplant Effects Questionnaire (TxEQ). Using a product-of-coefficients method, we compared the proposed models. Weaker cognitive performance was correlated with reduced adherence. Additionally, depressive symptoms (CES-D total score) and the CES-D Somatic Symptoms subscale, each partially mediated the relationship between cognition (PCA derived composite score) and TxEQ adherence scores. None of the other CES-D subscales were significant mediators. Conversely, cognition did not mediate the relationship between depressive symptoms and adherence. The CES-D Somatic Symptoms sub-scale (five questions) may have important utility as a predictor of medication adherence in renal transplant patients.