Association between uremic toxins and depression in patients with chronic kidney disease undergoing maintenance hemodialysis

Patients with chronic kidney disease (CKD) who are undergoing maintenance hemodialysis have a higher prevalence of depression than the general population. The underlying cause of this association is unknown, but may be related to accumulation of uremic toxins. Little is known about the association of accumulation of uremic toxins and depression in hemodialysis patients.We conducted a cross-sectional study of 209 CKD patients from a single institution to evaluate the associations of a soluble small uremic toxin (urea), a soluble large uremic toxin (β2 microglobulin) and two protein-bound uremic toxins [total p-cresol sulfate (PCS) and indoxyl sulfate (IS)] with the presence of depression.A total of 47 patients (22.4%) had depression. Depressive patients had lower body mass index, lower serum creatinine, lower serum albumin and lower total IS. Univariate and multivariate logistic regression analyses that adjusted for age, gender and other statistically significant variables indicated that depression was significantly and independently associated with lower serum albumin and lower total IS. The levels of urea, β2 microglobulin and PCS were not significantly associated with depression.Our results indicate that depression in patients with CKD was significantly and independently associated with lower serum albumin and lower total IS. However, the pathological mechanisms underlying these associations are unknown.