Cognitive impairment in patients with end-stage renal disease: Accelerated brain aging?

Chronic kidney disease exhibits a prominent premature aging phenotype in many different organ systems, including the brain. Nevertheless, a comprehensive characterization of brain aging in non-demented patients with end-stage renal disease (ESRD) is lacking and it remains unclear if the collective changes of cognitive functions and brain structures in ESRD is compatible with aging.

We compared 56 non-demented, independently living dialysis patients (mean age 59.4 ± 11.0 years; mean dialysis vintage of 5.9 years) and 60 non-dialysis controls on a battery of neuropsychological tests, brain MRI T1 imaging and diffusion tensor imaging. Participants with diagnosis of dementia, Mini-Mental State Examination <24, medical history of stroke, or recent hospitalization within 1 month were excluded.

Dialysis patients showed significantly worse performance in attention/information processing speed and executive function adjusted for age, sex, education, diabetes and depression. Reduced total brain volume and subcortical volume including hippocampus were found in dialysis patients. Vertex-wise analysis showed cortical thinning in middle frontal, lateral occipital and precuneus region. Furthermore, decreased white matter integrity was found primarily in bilateral anterior thalamic tract, fronto-occipital fasciculus, forceps minor and uncinate tract after correction for multiple comparisons.

Overall, differences in cognitive functions, cortical volumes/thickness and white matter integrity associated with dialysis are also cognitive domains and brain structure changes associated with normal aging. In other words, non-demented, independently living dialysis patients present an accelerated brain aging phenotype even after taking into account effects of age, diabetes and depression.