MILD COGNITIVE IMPAIRMENT (MCI) and cognitive impairment (CI) are highly prevalent among patients undergoing haemodialysis, with those experiencing overt cognitive impairment demonstrating significantly poorer physical function, according to new research.
In this cross-sectional study, researchers evaluated 147 outpatients receiving maintenance haemodialysis to determine the prevalence of cognitive dysfunction and its association with physical performance. The mean age of participants was 69.7 years, nearly two-thirds were male, and the average dialysis vintage was 6 years.
Cognitive status was assessed using two established screening tools: the Japanese version of the Montreal Cognitive Assessment (MoCA-J) to detect mild cognitive impairment, and the Mini-Mental State Examination (MMSE) to identify more advanced cognitive impairment. Participants were categorised into three groups: cognitively normal (MMSE ≥24 and MoCA-J ≥26), MCI (MMSE ≥24 and MoCA-J <26), and CI (MMSE <24).
Cognitive Impairment Is Highly Prevalent in Haemodialysis
Overall, cognitive impairment was common. Just 34% of patients were classified as cognitively normal, while 40% met criteria for MCI and 26% for CI. This means that two-thirds of the cohort had some degree of measurable cognitive dysfunction.
The study also examined physical function across groups, including grip strength, Short Physical Performance Battery (SPPB) scores, and usual gait speed. After adjustment for age, sex, dialysis vintage, and body mass index, patients in the CI group demonstrated significantly worse physical performance compared with both the normal and MCI groups. Measures of muscle strength, balance, and mobility were all reduced in those with CI.
In contrast, no significant differences in physical function were observed between patients classified as normal and those with MCI. This suggests that marked physical decline may become more apparent once cognitive impairment progresses beyond the mild stage.
Why Cognitive Screening Matters in Haemodialysis Care
The findings highlight the dual burden of cognitive and physical decline in the haemodialysis population. The authors suggest that routine cognitive and physical assessments may help to identify high-risk patients earlier, allowing for targeted interventions aimed at preserving independence, reducing frailty, and potentially improving overall outcomes in this vulnerable group.
Reference
Shimano Y et al. Association between cognitive and physical functions in patients undergoing haemodialysis. Nephrol. 2026; 31(2):e70175.
