This study looked at the relationship between frailty, cognitive impairment, and health outcomes in patients undergoing haemodialysis. Researchers used various tools to assess frailty and cognitive function in 448 participants, tracking them for nearly two years. They found that cognitive impairment was common, affecting 77.2% of participants, and that higher frailty scores were linked to poorer cognition. However, cognitive impairment was not directly associated with higher mortality or hospitalisation rates. Instead, the study showed that frailty and cognitive impairment together could identify patients at higher risk for hospital admissions. These findings suggest that evaluating both frailty and cognition is important for understanding the health risks in haemodialysis patients.

Abstract

Rationale & Objective

Frailty and cognitive impairment are common in haemodialysis recipients and have been associated with high mortality. There is considerable heterogeneity in frailty reporting, with little comparison between commonly used frailty tools and little exploration of the interplay between cognition and frailty. The aims were to explore the relationship between frailty scores and cognition and their associations with hospitalization and mortality.

Study Design

Prospective cohort study

Setting & Population

Prevalent haemodialysis recipients linked to national datasets for hospitalization and mortality.

Predictors

Montreal Cognitive Assessment (MoCA), Frailty Phenotype, Frailty Index (FI), Edmonton Frailty Scale, and Clinical Frailty Scale (CFS) were performed at baseline. Cognitive impairment was defined as MoCA scores of<26, or<21 in dexterity impairment, <18 in visual impairment.

Outcomes

Mortality, hospitalization.

Analytical Approach

Cox proportional hazards model for mortality, censored for end of follow-up. Negative binomial regression for admission rates, censored for death/end of follow-up.

Results

In total, 448 participants were recruited with valid MoCAs and followed up for a median of 685 days. There were 103 (23%) deaths and 1,120 admissions of at least one night. Cognitive impairment was identified in 346 (77.2%) participants. Increasing frailty by all definitions was associated with poorer cognition. Cognition was not associated with mortality (HR, 0.99; 95% CI, 0.95-1.03; P=0.41) or hospitalization (IRR, 1.01; 95% CI, 0.99-1.04; P=0.39) on multivariable analyses. There were interactions between MoCA scores and increasing frailty by FI (P=0.002) and Clinical Frailty Scale (P=0.005); admissions were highest when both MoCA and frailty scores were high, and when both scores were low.

Limitations

As frailty is a dynamic state, a single cross-sectional assessment may not accurately reflect its year-to-year variability. In addition, these findings are in maintenance dialysis and may not be transferable to incident haemodialysis. There were small variations in application of frailty tool criteria from other studies, which may have influenced the results.

Conclusions

Cognitive impairment is highly prevalent in this haemodialysis cohort. The interaction between cognition and frailty on rates of admission suggests the MoCA offers value in identifying higher risk haemodialysis populations with both high and low degrees of frailty.

Authors: Benjamin M Anderson, Muhammad Qasim, Gonzalo Correa Felicity Evison, Suzy Gallier Charles J Ferro Thomas A Jackson, Adnan Sharif