Cognitive Functioning Pre- to Post-kidney Transplantation--a Prospective Study

Background: Kidney transplantation (TX) may ameliorate the neuropsychological (NP) impairments in end-stage renal disease (ESRD). Previous studies have suffered from small sample sizes, lack of standardization of dialysis adequacy, and insufficiently sensitive NP tests.

Methods: Twenty-eight medically stable patients aged 44.04 (12.01) years with ESRD were investigated before and at 6 months after successful kidney TX using an NP test battery, which assessed attention-concentration, psychomotor ability and memory. Formal kinetic modelling of dialysis delivery ensured adequate renal replacement therapy. Transplant function was good on stable doses of immunosuppressive medication, without evidence of rejection at the time of testing.

Results: Within-subject comparisons showed statistically significant improvement in memory performance after kidney TX. Other NP measures (attention-concentration and psychomotor abilities) showed non-significant improvements. Normative comparisons showed NP impairments on dialysis, which were not apparent after TX.

Conclusion: These data demonstrate improvements in cognition following kidney TX and emphasize the reversibility of the memory problems evidenced in dialysis.