Alzheimer's disease cerebrospinal fluid biomarkers and kidney function in normal and cognitively impaired older adults

Abstract INTRODUCTION Recent Alzheimer's disease (AD) clinical trials have used cerebrospinal fluid (CSF) biomarker levels for screening and enrollment. Preliminary evidence suggests that AD risk is related to impaired renal function. The impact of kidney function on commonly used AD biomarkers remains unknown. METHODS Participants in studies conducted at the Goizueta Alzheimer's Disease Research Center (N = 973) had measurements of serum creatinine and CSF AD biomarkers. General linear models and individual data were used to assess the relationships between biomarkers and eGFR. RESULTS Lower estimated glomerular filtration rate (eGFR) was associated with lower amyloid beta (Aβ)42/tau ratio (p < 0.0001) and Aβ42 (p = 0.002) and higher tau (p < 0.0001) and p‐tau (p = 0.0002). The impact of eGFR on AD biomarker levels was more robust in individuals with cognitive impairment (all p‐values were < 0.005). DISCUSSION The association between eGFR and CSF AD biomarkers has a significant impact that varies by cognitive status. Future studies exploring this impact on the pathogenesis of AD and related biomarkers are needed. Highlights There is a significant association between Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers and both estimated glomerular filtration rate (eGFR) and mild cognitive impairment (MCI). Kidney function influences CSF biomarker levels in individuals with normal cognitive function and those with MCI. The impact of kidney function on AD biomarker levels is more pronounced in individuals with cognitive impairment. The variation in CSF tau levels is independent of cardiovascular factors and is likely directly related to kidney function. Tau may have a possible role in both kidney and cognitive function.