The Cohort Study of Cognitive Impairment in Chinese Hemodialysis Patients

Neuropsychological assessment All neuropsychological assessments were performed by the research staff that was centrally trained and certified by the study neuropsychologist to conduct the assessments before study commencement. All research staff and patients were native Chinese speakers. Neuropsychological assessment was conducted individually in a separate room on the day after a dialysis session and required on average approximately 90 minutes. Global cognitive function was screened by the Chinese Beijing version of the Montreal Cognitive Assessment (MoCA-BJ).10 The comprehensive battery of neuropsychological tests was designed to assess five cognitive domains: (1) attention/processing speed, using Symbol Digit Modalities Test and the Chinese modified version of the Trail Making Test A,11,12(2) executive function, using the Chinese modified version of the Trail Making Tests B , and a modified version of the Stroop Color-Word Test;13 (3) verbal memory, using the Chinese version of the Auditory Verbal Learning Test for short-delay and long-delay free recall14 and Complex Figure for visual memory (delayed recall test; Chinese version);12 (4) language, using the Chinese modified versions of Boston Naming Test (the 30-item version) and Animal Fluency Test;15,16and (5) visuospatial function, using the Rey-Osterrieth Complex Figure (copy test).17,18 Depression was assessed using the Hamilton Depression Scale, with scores ranging from 0 to 63 and a score of 7 or above suggested as the optimal cutoff for suspected depression.

Inclusion criteria

• Subjects have end-stage kidney disease and are treated with long-term outpatient haemodialysis in each investigational site for at least the previous 3 months;
• 50 ~ 80 years old;
• willing to provide written and informed consent.

Exclusion criteria

• Subjects have disturbance of consciousness or mental disorder;
• Subjects have sensory (visual and hearing) or motor impairment, which disabled them to complete the tests that required these senses;
• Subjects have a life expectancy less than 6 months according to their physician, have a planned kidney transplantation within 6 months of baseline, or have anticipated recovery of kidney function.