Pretransplant Cognitive Function and Kidney Transplant Outcomes: A Prospective Cohort Study

Abstract

Background and hypothesisCognitive impairment is common in patients being evaluated for a kidney transplant (KT). The association between pre-transplant cognitive function and post-transplant outcomes is unclear. Study DesignWe performed a prospective cohort study to assess the association between pre-transplant cognitive function and clinically relevant post-transplant outcomes. Setting and PopulationIn this single center study, participants from the transplant clinic were evaluated during their pre-transplant clinic visits and followed prospectively. OutcomesOur primary outcome measure was allograft function. Secondary outcomes were length of hospitalization for KT, hospital readmission within 30 and 90 days, graft loss, graft rejection within 90 days and one year, and mortality. Analytic approachWe measured cognitive function with the Montreal Cognitive Assessment (MoCA) test. We assessed the association of pre-transplant MoCA score with post-transplant outcomes; we used linear mixed effects models to assess the association with the change in estimated glomerular filtration rate (eGFR), Poisson regression for length of hospitalization, Cox proportional hazard model for graft loss and mortality, and a logistic regression model for readmission and rejection. ResultsWe followed 501 participants for 2.7±1.5 years. The mean age of the patients was 53±14 years and the mean pre-transplant MoCA score was 25±3. Lower pre-transplant MoCA scores did not adversely affect the primary outcome of allograft function or the secondary outcomes. Although higher MoCA scores predicted a higher decline in graft function (β -0.28, 95% CI -0.55, -0.01, p= 0.04), the effect was small and not clinically significant. Older age was associated with longer hospitalization, lower likelihood of rejection, and higher mortality. Deceased donor KT (vs. living donor KT) was associated with longer hospitalization but better graft function. Longer time on dialysis prior to KT was associated with longer hospitalization. A history of diabetes mellitus was associated with higher mortality. LimitationsSingle center study limiting generalizability. ConclusionsPre-transplant MoCA scores were not associated with the primary outcome of allograft function or the secondary outcomes.