Relationship Between Longitudinal Measures of Renal Function and Onset of Dementia in a Community Cohort of Older Adults

Abstract

Background Prior studies have described a higher incidence of dementia or worsening cognitive function in patients with lower levels of kidney function at a single point in time. Objectives To evaluate the association between dynamic measures of renal function ascertained over time with onset of dementia. Design prospective community cohort study. Setting and Participants 2,968 adults aged 65 and older followed for the development of dementia over a median of 6.0 years (interquartile range 3.1–10.1 years). Measurements Time varying measures of renal function were constructed based on a total of 49,340 serum creatinine measurements and included: the average level of estimated glomerular filtration rate (eGFR), eGFR trajectory and variability in eGFR around this trajectory over 5-year exposure windows. The association between these three eGFR exposure measures and risk of dementia was estimated using a Cox regression model adjusted for other patient characteristics. In sensitivity analyses, we also adjusted for time-varying measures of urine protein by dipstick. Results Patients with lower levels of eGFR had a higher incidence of dementia but this did not reach statistical significance in adjusted analyses (omnibus p value=0.14). There were trends toward a higher adjusted incidence of dementia in patients with positive eGFR trajectories (omnibus p value=0.07) and greater variability in eGFR (omnibus p value=0.04) over time. The results of sensitivity analyses, including those in which we included time-varying measures of proteinuria, were consistent with those of the primary analysis. Conclusion Among a community cohort of older adults followed for a median of 6 years, we did not find strong associations between measures of kidney disease severity and progression and incident dementia.

Estimated Glomerular Filtration Rate is not Associated with Alzheimer’s Disease in a Northern Ireland Cohort

“…Our findings support previous reports that showed no association between eGFR and cognitive impairment [6,[20][21][22], but contrast to those that did report a significant association [5,9,[23][24][25][26][27][28][29][30]. In addition, other studies also reported significant associations between renal impairment characterised by the presence of microalbuminuria and cognitive impairment [10,20,21,31].…”

Cognitive Impairment and Progression of CKD

“…24 Another study of 2968 adults aged 65 years or older found that increased eGFR variability, but not eGFR trajectory, was associated with an increased risk for dementia. 25 Thus, the existing literature supports the hypothesis that changes in cognitive function parallel changes in markers of kidney function.…”

Mid-Life Proteinuria and Late-Life Cognitive Function and Dementia in Elderly Men

“…The Adult Changes in Thought (ACT) Study found that those with lower eGFR had a higher incidence of dementia over 6 years of follow up, however there was no significance in adjusted analyses. 32 There were trends toward higher incident dementia among those with positive eGFR trajectories and greater variability in eGFR over time. The Osaki-Tajiri Project is a community-based study including 497 subjects (45% men) over 65 in an agricultural area of northern Japan.…”