Kidney Function and Cognitive Decline in Older Adults: Examining the Role of Neurodegeneration

BACKGROUND/OBJECTIVES Cognitive decline associated with impaired kidney function might involve neurodegeneration. Our objectives were to evaluate the longitudinal association between kidney function and cognitive decline in older adults and to assess the involvement of cortical beta‐amyloid and hippocampal atrophy (features of Alzheimer's disease (AD)) in this association. DESIGN Secondary analysis of the randomized controlled Multidomain Alzheimer Preventive Trial (MAPT). SETTINGS Thirteen memory centers (France and Monaco, 2008–2016). PARTICIPANTS A total of 1,334 community‐dwellers >70 years old without dementia at baseline. MEASUREMENTS We estimated glomerular filtration rate (eGFR) from serum creatinine using CKD‐Epi equation. Cognition was assessed at baseline, 6, 12, 24, 36, 48, and 60 months using a composite Z‐score designed for MAPT. The Clinical Dementia Rating (CDR) score was used to assess cognition and functional independence. We examined the association between eGFR and (1) evolution of the composite cognitive Z‐score using mixed‐effect models and (2) progression on CDR using Cox models and mixed‐effect models. Adjustments were made for age, sex, education, ApoE genotype, cardiovascular risk factors and disease, hippocampal volume (measured with magnetic resonance), and cortical beta‐amyloid (measured with positron emission tomography). RESULTS Median (IQR) eGFR was 73(60–84) mL/min/1.73 m2. Two hundred sixty‐nine participants experienced progression on CDR score during follow‐up. eGFR