Pre-transplant cognitive screening is a poor predictor of post-transplant cognitive status.

INTRODUCTION: Transplant centers hesitate to transplant patients with cognitive impairment. It is unclear if pre-kidney transplant (KT) cognitive screening can predict post-KT cognitive function. METHODS: We evaluated pre- to post-KT cognitive function with the Montreal Cognitive Assessment (MoCA) in a cohort of 108 patients. We used an adjusted logistic regression model to assess pre- to post-KT changes in cognitive status (continuous variable) and a linear mixed model to assess changes in MoCA scores (categorical variable) pre- to post- KT. RESULTS: The average pre- and post-KT MoCA scores were 25.3 ± 3.0 and 26.4 ± 2.8, respectively. Final pre-KT score did not predict post-KT cognitive status (OR = 1.08; 95% CI: .92-1.26; P = .35). 32% of the patients with a final pre-KT score ≥26 had at least one post-KT score < 26. Conversely, 61% of the patients with a final pre-KT score < 26 had at least one post KT score ≥26. In the linear mixed model analysis, the final pre-KT score was associated with a small, clinically insignificant (ß = .34; 95% CI: .19-.49; P < .001) effect on the post-KT score. CONCLUSION: A low pre-KT MoCA score is not a strong independent predictor of post-KT cognitive function and should not preclude patients from receiving a KT.

Prevalence and correlates of cognitive impairment in kidney transplant recipients.

BACKGROUND: There is a high prevalence of cognitive impairment in dialysis patients. The prevalence of cognitive impairment after kidney transplantation is unknown. METHODS: Study Design: Cross-sectional study. SETTING AND PARTICIPANTS: Single center study of prevalent kidney transplant recipients from a transplant clinic in a large academic center. INTERVENTION: Assessment of cognition using the Montreal Cognitive Assessment (MoCA). Demographic and clinical variables associated with cognitive impairment were also examined. Outcomes and Measurements: a) Prevalence of cognitive impairment defined by a MoCA score of <26. b) Multivariable linear and logistic regression to examine the association of demographic and clinical factors with cognitive impairment. RESULTS: Data from 226 patients were analyzed. Mean (SD) age was 54 (13.4) years, 73% were white, 60% were male, 37% had diabetes, 58% had an education level of college or above, and the mean (SD) time since kidney transplant was 3.4 (4.1) years. The prevalence of cognitive impairment was 58.0%. Multivariable linear regression demonstrated that older age, male gender and absence of diabetes were associated with lower MoCA scores (p < 0.01 for all). Estimated glomerular filtration rate (eGFR) was not associated with level of cognition. The logistic regression analysis confirmed the association of older age with cognitive impairment. CONCLUSION: Cognitive impairment is common in prevalent kidney transplant recipients, at a younger age compared to general population, and is associated with certain demographic variables, but not level of eGFR.

Subclinical Cognitive Impairment and Listing for Kidney Transplantation.

BACKGROUND AND OBJECTIVES: Cognitive impairment is common in patients with kidney disease and can affect physicians' perception and/or patients' ability to complete the pretransplant evaluation. We examined whether cognitive impairment influences the likelihood for transplant listing and whether patients with cognitive impairment take longer to be listed. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a single-center longitudinal cohort study. Patients presenting for their index kidney transplant evaluation were screened for cognitive impairment using the Montreal Cognitive Assessment. A score <26 indicated cognitive impairment. The transplant selection committee was blinded to the scores. Kaplan-Meier analysis assessed time to active listing by level of cognition. A Cox proportional hazards model that included age, sex, race/ethnicity, smoking, coronary artery disease, and diabetes was constructed to evaluate the association between Montreal Cognitive Assessment score and listing for transplant. RESULTS: In total, 349 patients who underwent Montreal Cognitive Assessment testing at their initial visit were included in the analysis. Patients with cognitive impairment were more likely to be older, black, and smokers. The time to listing in patients with cognitive impairment was longer than the time to listing in those with no cognitive impairment (median time, 10.6 versus 6.3 months; log rank test P=0.01). Cognitive impairment was independently associated with a lower likelihood of being listed for transplant (hazard ratio, 0.93 per unit lower Montreal Cognitive Assessment score; 95% confidence interval, 0.88 to 0.99; P=0.02). A lower proportion of patients with cognitive impairment were listed compared with patients without cognitive impairment at 1 month (2% versus 11%), 6 months (17% versus 37%), and 1 year (23% versus 41%), (P<0.001 for all). CONCLUSIONS: Cognitive impairment is associated with a lower likelihood of being listed for kidney transplant, and is associated with longer time to transplant listing.

Discrepancies between Perceived and Measured Cognition in Kidney Transplant Recipients: Implications for Clinical Management.

BACKGROUND: Cognitive impairment is common in kidney transplant (KT) recipients and affects quality of life, graft survival, morbidity, and mortality. Failure to identify patients with cognitive impairment can withhold appropriate and timely intervention. This study determines whether measured cognition with standard screening tools offers any advantage over perceived cognition in screening transplant patients for cognitive impairment. METHODS: Cognition was assessed in 157 KT recipients using the Montreal Cognitive Assessment (MoCA; measured cognition). In addition, transplant physicians and nurse coordinators were asked to rate transplant recipients' level of cognition after routine clinical interactions (perceived cognition). Physicians and nurses were blind to MoCA scores. Perceived cognition scores were compared to MoCA scores. RESULTS: Perceived cognition scores fairly correlated with MOCA scores (γ = 0.24, p = 0.001 for physicians and γ = 0.33, p < 0.0001 for nurses). Physician scores moderately correlated with nurses scores (κ = 0.44, p < 0.0001). Clinical perception had a low accuracy for identifying patients with cognitive impairment (sensitivity 66% for physicians, 65% for nurses), and those without cognitive impairment (specificity 67% for physicians, 76% for nurses). CONCLUSION: Clinical perception is inaccurate at detecting cognitive impairment in KT recipients. Objective tests should be considered to screen KT recipients for cognitive impairment.