Association Between Cognitive and Physical Functions in Patients Undergoing Haemodialysis

AIM: This study aimed to determine the prevalence of mild cognitive impairment (MCI) and cognitive impairment (CI) in patients undergoing haemodialysis (HD) and to identify physical function characteristics associated with these conditions. METHODS: A cross-sectional study was conducted among 147 outpatients receiving HD. MCI was evaluated using the Japanese version of the Montreal Cognitive Assessment (MoCA-J), and CI was assessed using the Mini-Mental State Examination (MMSE). Patients were classified into three groups: normal (MMSE ≥ 24 and MoCA-J ≥ 26), MCI (MMSE ≥ 24 and MoCA-J < 26) and CI (MMSE < 24). Patient characteristics and physical function were compared among groups. Multivariate analysis was conducted using analysis of covariance adjusted for age, sex, dialysis vintage and body mass index. RESULTS: The mean age of participants was 69.7 ± 11.8 years, 63.9% were male, and the mean HD vintage was 6.0 ± 6.9 years. Based on cognitive testing, 50 patients (34%) were classified as normal, 59 (40%) as MCI and 38 (26%) as CI. Compared with the normal group, the CI group exhibited significantly lower physical function, including grip strength, Short Physical Performance Battery scores, and usual gait speed. Similarly, physical function in the CI group was significantly poorer than in the MCI group. However, no significant differences in physical function were observed in physical function between the normal and MCI groups. CONCLUSION: MCI and CI were prevalent among HD patients, affecting 40% and 26%, respectively. Patients with CI demonstrated a marked decline in physical function than those who were cognitively normal or had MCI.