Chronic kidney disease is associated with incident cognitive impairment in the elderly: the INVADE study.
BACKGROUND
Limited data exist regarding the relationship between decreased renal function and cognitive impairment.


METHODS
A total of 3679 participants of the Intervention Project on Cerebrovascular Diseases and Dementia in the Community of Ebersberg (INVADE) composed the community-based cohort study. Measures of renal function were estimated using the Cockcroft-Gault equation and divided into normal, mild and moderate-to-severe impaired renal function (creatinine clearance >or=60, 45-59 and <45 mL/min/1.73 m(2), respectively). The main outcome measures were cognitive impairment at baseline and new cognitive impairment after a 2-year follow-up. Cognitive function was measured using the 6-Item Cognitive Impairment Test (6CIT). Multiple logistic regression analysis was used to assess the association between renal function and cognitive impairment.


RESULTS
At baseline, 396 participants (10.8%) had cognitive impairment. After the 2-year follow-up, 194 participants (6.2%) developed new cognitive impairment. The incidence of cognitive impairment across the groups with normal renal function, mild and moderate-to-severe kidney disease at baseline were 5.8, 9.9 and 21.5%, respectively. Multiple logistic regression analysis after adjustment for possible confounders including traditional cardiovascular risk factors showed a significant association for participants with moderate-to-severe kidney disease at baseline to develop new cognitive impairment after the 2-year follow-up [odds ratio: 2.14 (95% confidence interval: 1.18-3.87), P = 0.01].


CONCLUSIONS
In summary, moderate-to-severe impaired renal function is associated with incident cognitive impairment after 2 years in a large cohort of elderly subjects.
Etgen
Thorleif
T
Department of Psychiatry and Psychotherapy, Technische Universität München, Munich, Germany. thorleif.etgen@klinikum-traunstein.de
Sander
Dirk
D
Chonchol
Michel
M
Briesenick
Claus
C
Poppert
Holger
H
Förstl
Hans
H
Bickel
Horst
H
D000368:Aged; D002908:Chronic Disease; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000150:complications*; D008297:Male; D011446:Prospective Studies