Cognitive Decline and Haemodialysis: A Growing Concern
Cognitive impairment is increasingly recognized as a significant health issue among individuals undergoing haemodialysis. New research indicates a high prevalence of both mild cognitive impairment (MCI) and more severe cognitive decline in this patient population, with a demonstrable link to poorer physical function. Understanding this connection is crucial for improving the quality of life and overall outcomes for those reliant on dialysis.
Prevalence of Cognitive Impairment in Haemodialysis Patients
Studies reveal a concerning rate of cognitive dysfunction in patients receiving haemodialysis. A recent cross-sectional study evaluating 147 outpatients on maintenance haemodialysis found that only 34% were classified as cognitively normal. A substantial 40% met the criteria for MCI, and 26% exhibited signs of cognitive impairment (CI).1 This means approximately two-thirds of patients undergoing haemodialysis experience some degree of cognitive impairment.
Impact on Physical Function
The study highlighted a clear correlation between cognitive status and physical performance. Patients with CI demonstrated significantly worse performance in measures of muscle strength, balance, and mobility compared to those with normal cognitive function. Specifically, grip strength, Short Physical Performance Battery (SPPB) scores, and usual gait speed were all reduced in the CI group.1 Interestingly, no significant differences in physical function were observed between patients with normal cognition and those with MCI, suggesting that a more pronounced physical decline becomes apparent as cognitive impairment progresses.
Assessing Cognitive Function
Researchers utilized established screening tools to assess cognitive status. The Japanese version of the Montreal Cognitive Assessment (MoCA-J) was used to detect MCI, while the Mini-Mental State Examination (MMSE) identified more advanced cognitive impairment.1 These tools help categorize patients into three groups: cognitively normal (MMSE ≥24 and MoCA-J ≥26), MCI (MMSE ≥24 and MoCA-J <26), and CI (MMSE <24).1
Why Cognitive Screening Matters
The findings underscore the importance of routine cognitive and physical assessments for patients undergoing haemodialysis. Early identification of high-risk individuals allows for targeted interventions aimed at preserving independence, reducing frailty, and potentially improving overall outcomes.1 Addressing cognitive impairment in this vulnerable population is critical, as it contributes to a dual burden of cognitive and physical decline.
Underlying Mechanisms and Future Directions
Research suggests that dialysis treatment itself may play a central role in the pathophysiology of cognitive impairment.3 Both haemodialysis and peritoneal dialysis are associated with structural and functional changes in the brain, leading to symptoms like headache, confusion, and “brain fog,” as well as long-term reductions in cognitive ability.3 White-matter injury is particularly common in dialysis patients and is often linked to deficits in executive functioning.3 Alzheimer’s disease and vascular cognitive impairment are too frequently observed, sometimes occurring in combination.3
Further research is needed to fully elucidate the mechanisms driving cognitive impairment in haemodialysis patients and to develop effective therapeutic interventions.3
Key Takeaways
- Cognitive impairment is highly prevalent in patients undergoing haemodialysis, affecting approximately two-thirds of the population.
- Cognitive impairment is strongly associated with poorer physical function, including reduced muscle strength, balance, and mobility.
- Routine cognitive and physical assessments are crucial for early identification and intervention.
- Dialysis treatment itself may contribute to cognitive decline through various mechanisms.
1 Shimano Y et al. Association between cognitive and physical functions in patients undergoing haemodialysis. Nephrol. 2026;31(2):e70175.
3 Nature Reviews Nephrology. Dialysis and cognitive impairment. https://www.nature.com/articles/s41581-025-00960-3