The Ratio of Plasma Amyloid-β 1-42 over Serum Albumin Can Be a Novel Biomarker Signature for Diagnosing End-Stage Renal Disease-Associated Cognitive Impairment

Background: Cognitive impairment (CI) is one of the major complications in chronic kidney disease patients, especially those with end-stage renal disease (ESRD). Limited biomarkers have been found that can significantly predict ESRD-associated cognitive decline. Objective: This cohort study aimed to investigate de novo biomarkers for diagnosis of the ESRD-associated CI. Methods: In this cohort study, qualified samples were divided into control (with an estimated glomerular filtration rate (eGFR) of≥60 mL/min and a Mini-Mental State Examination (MMSE) score of > 27), ESRD without CI (eGFR < 15 and MMSE > 27), and ESRD with CI (eGFR < 15 and MMSE < 27) groups. Levels of plasma amyloid-β (Aβ)1 - 42, serum indoxyl sulfate, and hematologic and biochemical parameters were measured. Results: Compared to the control group, levels of blood urea nitrogen, creatinine, and indoxyl sulfate were elevated in ESRD patients both without and with CI. Interestingly, ESRD patients with CI had the lowest levels of serum albumin. In contrast, levels of plasma Aβ1 - 42 were significantly higher in the ESRD with CI group than in the control and ESRD without CI groups. In addition, the ratio of plasma Aβ1 - 42 over serum albumin was significantly higher in the ESRD with CI group than in the control or ESRD without CI groups. Importantly, the area under the receiver operating characteristic curve (AUROC) for CI in the total population by the ratio of Aβ1 - 42 over albumin was 0.785 and significant (p < 0.05). Conclusions: This cohort study has shown that the ratio of plasma Aβ1 - 42 over serum albumin can be a de novo biomarker for the diagnosis and prognosis of ESRD-associated cognitive decline.