This study is going to apply neuropsychological battery tests to measure cognitive function across multiple cognitive domains in our cohort of 600 maintenance hemodialysis patients and evaluate:

1. The presence and patterns of cognitive impairment in domains of executive function, perceptual-motor function, language, learning and memory, and complex attention;
2. Clinical characteristics of participants with and without cognitive impairment;
3. the risk factors which might be related to cognitive impairment in this group of population;
4. The association between cognitive impairment and all-cause mortality, stroke and non-fatal cardiovascular events;

We hypothesize that hemodialysis patient is going to have cognitive impairment which might be associated with some risk factors. We also anticipate that cognitive impairment might have some kind of association with the clinical outcomes like all-cause mortality, stroke and other common clinical outcomes that we mentioned above.

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:

1. 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;
2. 50 ~ 80 years old;
3. willing to provide written and informed consent.

Exclusion Criteria:

1. Subjects have disturbance of consciousness or mental disorder;
2. Subjects have sensory (visual and hearing) or motor impairment, which disabled them to complete the tests that required these senses;
3. 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.

Chinese Maintenace Hemodialysis Patients