End-stage renal disease (ESRD) patients are at substantially higher risk for developing cognitive impairment compared with the healthy population. Dialysis is an essential way to maintain the life of ESRD patients. Based on previous research, there did not provide an uncontested result whether cognition was improved or worsened during dialysis.
To explore the impact of dialysis treatment on cognitive performance, we recruited healthy controls (HCs), ESRD patients before dialysis initiation (bESRD) and those undergoing maintenance hemodialysis (mESRD). All ESRD patients performed a serious of blood biochemistry tests (hemoglobin, urea, cystatin C, Na+, K + and parathyroid hormone). Neuropsychological tests were used to measure cognitive function. By using diffusion tensor imaging and graph-theory approaches, the topological organization of the whole-brain structural network was investigated. Generalized linear models (GLMs) were performed to investigate blood biochemistry predictors of the neuropsychological tests and the results of graph analyses in mESRD and bESRD groups.
Neuropsychological analysis showed mESRD exhibited greater cognitive function than bESRD, but both were worse than HCs. Whole-brain graph analyses revealed that increased global efficiency and normalized shortest path length remained in the bESRD and mESRD than the HCs. Besides, lower normalized clustering coefficient was in bESRD relative to the HCs and mESRD. For the GLMs analysis, only the Cystatin C level was significantly associated with the average fiber length of rich club connections in bESRD.
Our study revealed that dialysis had a limited effect on cognitive improvement. Cystatin C may be a risk feature of cognitive decline of bESRD.