Cognitive function after kidney transplantation: longitudinal trajectories, associated factors, and clinical outcomes-a systematic review.

BACKGROUND: Cognitive impairment is common in patients with advanced kidney disease and may persist after kidney transplantation (KT). This systematic review synthesized evidence on posttransplant cognitive trajectories, associated factors, and clinical outcomes. METHODS: PubMed, Embase, and Web of Science were searched from inception through July 21, 2026. After screening and citation searching, 22 reports were included. Eligible studies included longitudinal studies assessing cognitive trajectories or studies evaluating associations between cognitive function and posttransplant clinical outcomes among adult kidney transplant recipients. Due to heterogeneity in cognitive measures and follow-up intervals, findings were synthesized narratively rather than conducting meta-analysis. Certainty of evidence for the trajectory of cognitive domains was assessed using GRADE. RESULTS: Global cognition showed no consistent improvement after KT, whereas more favorable changes were observed in selected measures of processing and psychomotor speed, verbal learning and immediate memory, and delayed verbal memory and recall. Findings for attention, executive function, verbal fluency, visuospatial and constructional function, and working memory were mixed or limited. Certainty of evidence was low for delayed verbal memory and recall, and very low for all other cognitive domains. Studies examined a range of factors associated with cognitive function after KT, including demographic, kidney disease-related, transplantation-related, comorbidity, physical function, and neuroimaging-derived brain-related factors. But the evidence was sparse and inconsistent. Three reports suggested potential associations between cognitive impairment and mortality or allograft loss. CONCLUSION: Cognitive change after KT may be domain-specific. Current evidence remains uncertain due to heterogeneous follow-up period, incomplete adjustment for confounding, lack of a comparison group, and other methodological limitations.