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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.