Background: Cognitive impairment is associated with poorer quality of life, risk for hospitalization, and mortality. Cognitive impairment is common in people with end-stage kidney disease treated with hemodialysis, yet the severity and specific cognitive deficits are uncertain.
Study design: Systematic review and meta-analysis.
Setting & population: Adults receiving hemodialysis compared with the general population, people with non-dialysis-dependent chronic kidney disease (NDD-CKD), people receiving peritoneal dialysis, or people with nondialyzed chronic kidney failure.
Selection criteria for studies: Randomized controlled trials, cohort or cross-sectional studies without language restriction.
Index tests: Validated neuropsychological tests of cognition.
Outcomes: Cognitive test scores, aggregated by cognitive domain: orientation and attention, perception, memory, language, construction and motor performance, concept formation and reasoning, and executive functions.
Results: 42 studies of 3,522 participants. Studies were of high or uncertain risk of bias, assessed by the Newcastle-Ottawa Scale. People treated with hemodialysis had worse cognition than the general population, particularly in attention (n=22; standardized mean difference [SMD], -0.93; 95% CI, -1.18 to -0.68). Hemodialysis patients performed better than nondialyzed patients with chronic kidney failure in attention (n=6; SMD, 0.70; 95% CI, 0.45 to 0.96) and memory (n=6; SMD, 0.36; 95% CI, 0.08 to 0.63), but had poorer memory than the general population (n=16; SMD, -0.41; 95% CI, -0.91 to 0.09) and people with NDD-CKD (n=5; SMD, -0.40; 95% CI, -0.60 to -0.21). There were insufficient data to show other differences among people receiving hemodialysis and those receiving peritoneal dialysis or with NDD-CKD.
Limitations: Potentially biased studies, not wholly adjusted for education. High heterogeneity, mainly due to the large variety of tests used to assess cognition.
Conclusions: People treated with hemodialysis have impaired cognitive function compared to the general population, particularly in the domains of orientation and attention and executive function. Cognitive deficits in specific domains should be further explored in this population and should be considered when approaching education and chronic disease management.
Keywords: Cognition; RRT modality; attention; chronic disease management; cognitive impairment; end-stage kidney disease (ESKD); executive function; hemodialysis; memory; meta-analysis; neuropsychological tests; orientation; renal replacement therapy (RRT); systematic review.
Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.