Subclinical Cognitive Impairment and Listing for Kidney Transplantation

Abstract

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.

Keywords: Cognition; Cognitive Dysfunction; Cohort Studies; ESKD; Kaplan-Meier Estimate; Kidney Diseases; Longitudinal Studies; Mental Status and Dementia Tests; Proportional Hazards Models; Smokers; Smoking; cognition; coronary artery disease; diabetes mellitus; eligibility; kidney transplantation.

Graphical abstract

Figure 1.

Time to listing was more for patients with lower Montreal Cognitive Assessment (MoCA) scores. Kaplan–Meier incidence [1-S(t)] plots for time to active listing by MoCA score. The three categories were MoCA scores ≤18, 19–25, and ≥26. Log rank test P=0.01.

Figure 2.

Older patients (>50 years of age) with cognitive impairment took longer to get listed compared to patients without cognitive impairment. Kaplan-Meier incidence [1-S(t)] plots for time to active listing stratified by age and MoCA score. Solid lines represent no cognitive impairment and dotted lines represent cognitive impairment. For patients 50–59 years, log-rank test P=0.05; for patients ≥60 years, P=0.01, and for <50 years, P=0.7.

Figure 3.

Patients with lower Montreal Cognitive Assessment (MoCA) scores were declared ineligible sooner than those with higher MoCA scores. Kaplan–Meier incidence [1-S(t)] plots for time to being declared ineligible or removed from the waitlist by Montreal Cognitive Assessment score. The three categories were MoCA scores ≤18, 19–25, and ≥26. Log rank test P=0.003.