Associations Between Kidney Function and Risk of Cognitive Impairment Among Chinese Older Adults

The association between kidney function and dementia remains inconsistent across studies, and its relationship in older adults is unclear. This study aimed to investigate the longitudinal associations between kidney dysfunction, assessed by estimated glomerular filtration rate (eGFR) and albuminuria, and cognitive impairment (CI) in a national cohort of Chinese older adults.

We included individuals aged ≥ 65 years from the 2011 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination (MMSE). Kidney function was evaluated by eGFR (CKD-EPI equation) and the urinary albumin-to-creatinine ratio (ACR), classified by KDIGO categories and quartiles. Multivariable logistic regression models were used to assess cross-sectional (n = 3364) and prospective (n = 1195) associations, controlling for sociodemographic and clinical confounders. The false discovery rate was controlled for multiple comparisons.

In cross-sectional analysis, both lower eGFR and higher ACR were independently associated with higher odds of prevalent CI. Prospectively, over a 3-year follow-up, 143 of 1195 cognitively normal participants developed CI. Compared to those with normal kidney function, participants with impaired (eGFR < 60 mL/min/1.73 m²) kidney function had a significantly higher risk of incident CI (OR = 1.744, 95% CI: 1.162-2.616). Similarly, elevated ACR (categories A2 and A3) was associated with increased incident CI risk (A2: OR = 1.801, 95% CI: 1.111-2.920; A3: OR = 2.650, 95% CI: 1.541-4.557).

Impaired kidney function, indicated by reduced eGFR and elevated ACR, is independently associated with an increased risk of cognitive impairment in older adults. These findings support integrating cognitive screening into the clinical management of elderly patients with chronic kidney disease.