Changes in Cognitive Function After Kidney Transplantation: A Longitudinal Cohort Study

Kidney disease negatively affects cognition. We assessed the effect of kidney transplantation (KT) on different cognitive domains. Prospective cohort study. We examined pre- versus post-KT cognition in patients waitlisted for KT at an academic center. Transplant status. We measured cognitive function before KT (n=101), 3 months after KT (n=78), and 1 year after KT (n = 83). Our primary outcome was change in cognitive function before versus after KT. We used standard neuropsychological tests to assess global cognition (Mini-Mental State Exam [MMSE]), episodic/declarative memory (Logical Memory), psychomotor speed/visuospatial function (Digit Symbol Substitution Test [DSST], Trail Making Test [TMT] A), working memory/attention (Digit Span), executive function (TMT B), and semantic memory/verbal fluency/language (Category Fluency). Using linear mixed model analysis, we evaluated the changes in neuropsychological test scores adjusted for age, sex, race, education, and number of assessments. Before KT, Logical Memory I and II, DSST, MMSE, Category Fluency (animal naming), and Digit Span backward scores were low compared with normative values from the National Alzheimer’s Coordinating Center data. Logical Memory I and II scores improved after KT (pre- vs post-KT, estimated group difference [d]=3.3, P