Reduced kidney function is associated with poorer domain‐specific cognitive performance in community‐dwelling older adults

OBJECTIVES: Whilst chronic kidney disease has been associated with cognitive impairment, the association between reduced estimated Glomerular Filtration Rate (eGFR) and domain‐specific cognitive performance is less clear and may represent an important target for the promotion of optimal brain health in older adults. METHODS: Participants aged >60 years from the Trinity‐Ulster‐Department of Agriculture study underwent detailed cognitive assessment using the Mini‐Mental State Examination (Mini‐Mental State Examination (MMSE)), Frontal Assessment Battery (FAB) and Repeatable Battery for Assessment of Neuropsychological Status (RBANS). Poisson and linear regression models assessed the relationship between eGFR strata and cognitive performance. RESULTS: In 4887 older adults (73.9 ± 8.3 years; 67.7% female), declining eGFR strata was associated with greater likelihood of error on the MMSE/FAB and poorer overall performance on the RBANS. Following robust covariate adjustment, findings were greatest for GFR <45 ml/ml/1.73 m(2) (Incidence Rate Ratio: 1.17; 95% CI 1.08, 1.27; p < 0.001 for MMSE; IRR: 1.13; 95% CI 1.04, 1.13; p < 0.001 for FAB; β: −3.66; 95% CI −5.64, −1.86; p < 0.001 for RBANS). Additionally, eGFR <45 ml/ml/1.73 m(2) was associated with poorer performance on all five RBANS domains, with greatest effect sizes for immediate memory, delayed memory and attention. Associations were strongest in those aged 60–70, with no associations observed in those >80 years. CONCLUSIONS: Reduced kidney function was associated with poorer global and domain‐specific neuropsychological performance. Associations were strongest with eGFR <45 ml/min/1.73 m(2) and in those aged 60–70 years, suggesting that this population may potentially benefit from potential multi‐domain interventions aimed at promoting optimal brain health in older adults.