Abstract

Background

It is important to learn more about the prevalence, severity and characteristics (i.e., which cognitive abilities are especially affected) of cognitive impairment in kidney transplant patients. Furthermore, the impact of living vs. deceased donor renal transplantation on cognitive outcome in this patient group needs further studies.

Methods

Fifty-nine patients (43 men, age 55 ± 13 years) who received a deceased donor or living donor kidney transplant, completed a comprehensive neuropsychological test assessment. Neuropsychological tests explored the cognitive domains of verbal and visual memory, attention, and executive functions.

Results

Fifteen percent  of the patients had mild, 25% moderate, and 15% severe cognitive impairment. The level of domain-specific cognitive deficit differed between verbal memory, attention, and executive functions (χ²(2) = 7.11, p = 0.029). On average, patients showed the highest deficit in executive functions, and the lowest deficit in verbal memory. Patients who received a kidney graft from a deceased donor were more likely to have a cognitive impairment than those who received a kidney graft from a living donor (OR = 3.03, 95% CI [0.99,9.32], Wald χ²₍₁₎ = 3.74, p = 0.053). This effect was independent of time on dialysis as well as of creatinine levels, or creatinine clearance.

Conclusions

Our results show that in kidney transplant patients with cognitive impairment, the cognitive domain of executive functions is the most affected one. This might be detrimental for quality of life. The fact that patients who received living donor kidneys seem to do better in terms of cognition than patients with deceased donor kidneys deserves more attention in future research.

Graphical abstract