NDT Advance Access originally published online on May 21, 2009
Nephrology Dialysis Transplantation 2009 24(10):3144-3150; doi:10.1093/ndt/gfp230
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Chronic kidney disease is associated with incident cognitive impairment in the elderly: the INVADE study
1 Department of Psychiatry and Psychotherapy, Technische Universität München, Munich 2 Department of Neurology, Klinikum Traunstein, Traunstein 3 Department of Neurology, Technische Universität München, Munich 4 Department of Neurology, Medical Park Hospital, Bischofswiesen, Germany 5 Division of Renal Diseases and Hypertension, University of Colorado Denver Health Sciences Center, Box C-280, Denver, CO 80262, USA 6 INVADE Study Group, Ebersberg, Germany
Correspondence and offprint requests to: Thorleif Etgen; E-mail: thorleif.etgen{at}klinikum-traunstein.de
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Abstract |
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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 
60, 45–59 and <45 mL/min/1.73 m2, 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.
Keywords: chronic kidney disease; cognitive impairment; elderly
Received for publication: 23. 2.09
Accepted in revised form: 27. 4.09