Level of kidney function correlates with cognitive decline

Early stage chronic kidney disease has been related to cognitive decline recently, while the association between them has never been explored in a Chinese population.

This prospective study included a 1,351 community-based Chinese population >40 years and with estimated glomerular filtration rate (eGFR) >30 ml/min/ 1.73 m(2). Kidney function was assessed by eGFR at baseline; cognitive function was evaluated by Mini-Mental State Examination (MMSE) both at baseline and 4 years later, and MMSE score decreased < or =2 was defined as cognitive decline using analysis of Reliable Change Indices. There were 1,243 participants (92.0%) with valid data of MMSE at the second visit.

Altogether there were 66 (5.3%) incident cognitive decline cases during 4 years of follow-up. After adjusting for potential confounders including urinary albumin-to-creatinine ratio, the odds ratio of developing cognitive decline was 1.35 (95% CI 0.69-2.65) among participants with eGFR 60-89 ml/min/1.73 m(2) and was 2.73 (95% CI 1.00-7.56) among participants with eGFR 30-59 ml/min/1.73 m(2), compared to those with eGFR > or =90 ml/min/1.73 m(2).

Our prospective study suggests that kidney function is associated with a cognitive decline in a Chinese population and the relation is independent of urinary albumin excretion.