Association between chronic kidney disease and depressive symptoms: a cross-sectional and mediation analysis

Chronic kidney disease (CKD) is a clinical syndrome characterised by declining renal function, linked to depressive symptoms, though the mediating role of biochemical markers in this association remains unclear. We downloaded and analyzed data from the National Health and Nutrition Examination Survey (NHANES) spanning from 2005 to 2018. This study employed multivariate logistic regression, restricted cubic spline models, subgroup analyses, and interaction tests to investigate the association between CKD and depressive symptoms. Additionally, mediation analyses assessed the potential role of biochemical markers in the relationship between CKD and depressive symptoms. A total of 2902 CKD participants were included, with 291 presenting depressive symptoms, and estimated glomerular filtration rate (eGFR) was negatively associated with depressive symptoms with full adjustment [odds ratio (OR), 0.98; 95% confidence interval (95% CI), 0.97–1.00]. After converting eGFR to a categorical variable by quartiles (Q1-Q4), compared to Q1, the highest eGFR quartile was linked to a significantly decreased likelihood of depressive symptoms (OR=0.53, 95% CI: 0.30–0.92). Subgroup analysis further revealed a negative relationship between eGFR and depressive symptoms. Mediation analysis indicated that six biochemical markers mediated the association between CKD and depressive symptoms, with the following contributions: 49.72% for blood urea nitrogen, 17.82% for alkaline phosphatase, 17.21% for albumin, 9.78% for globulin, 8.94% for iron, and 6.95% for glucose. In this cross-sectional analysis, lower eGFR was associated with higher presence of depressive symptoms. Blood urea nitrogen, alkaline phosphatase, albumin, globulin, iron, and glucose mediated the association of CKD on depressive symptoms.