Kidney disease linked to cognitive impairment: from the annual meeting of the American academy of neurology.
"Clinicians think about the apo E4 gene, advanced age, education level, and history of stroke as being risk factors for cognitive impairment, but they don't think about chronic kidney disease as a risk factor," Dr. Anne M. Murray said in an interview during a poster session at the meeting. "It's a strong risk factor."
Recent studies suggest a link between estimated glomerular filtration rate (GFR) and cognitive function, but the severity of cognitive impairment and effects on specific cognitive domains remain unknown said Dr. Murray, a geriatrician and neuro-epidemiologist at Hennepin County Medical Center, Minneapolis.
She and her associates at two Minneapolis clinics compared the frequency of mild, moderate, and severe cognitive impairment in 81 patients with an estimated GFR of less than 50 mL/min per 1.73 [m.sup.2] (stage 3B to stage 5 chronic kidney disease) against 338 hemodialysis patients and 101 controls. The patients with chronic kidney disease had a mean estimated GFR of 31 mL/min per 1.73 [m.sup.2]. The researchers administered a 45-minute battery of nine validated neuropsychological tests to patients with chronic kidney disease (CKD) and to controls, while hemodialysis patients were tested before dialysis, 1 hour after, or on the day after dialysis. They used the Modified Mini-Mental State Examination (maximum score, 100) to measure global cognitive function, and other tests to measure performance in the domains of memory, executive function, and language.
African Americans made up 59% of the CKD group, 11% of the hemodialysis group, and 8% of controls. Mean ages in the CKD, hemodialysis, and control groups were 60, 71, and 69 years, respectively. Prevalence of mild cognitive impairment was 7%, 14%, and 14%; moderate cognitive impairment 46%, 36%, and 27%; severe cognitive impairment 31%, 37%, and 13%; and normal cognitive function 16%, 13%, and 47%.
The mean Modified Mini-Mental State Examination score was 92.0 in the CKD group (consistent with early mild cognitive impairment), 88.3 in the hemodialysis group (consistent with early dementia), and 94.3 among controls (consistent with normal cognitive function).
Black race was strongly associated with severe cognitive impairment among patients with CKD (P less than .015), but no other significant bivariate associations were observed between cognitive status and demographic factors, estimated GFR, or history of stroke, in part because of the study's small sample size.
If patients have moderate chronic kidney disease - an estimated GFR of less than 50 mL/min per 1.73 [m.sup.2] - "they should be screened for cognitive impairment, because they probably can't take their medications on their own, and their judgment is probably impaired when it comes to making a decision about starting dialysis," Dr. Murray noted.
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Major Finding: The prevalence of moderate cognitive impairment was 46% among patients with moderate chronic kidney disease, 36% among patients receiving hemodialysis, and 27% among controls.
Data Source: An ongoing prospective study of 81 patients with moderate chronic kidney disease, 338 patients receiving hemodialysis, and 101 controls.
Disclosures: The study was funded by the Minneapolis Medical Research Foundation, Satellite Healthcare, and the National Institute on Aging. Dr. Murray said she had no relevant financial disclosures.
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|Title Annotation:||ACROSS SPECIALTIES|
|Publication:||Clinical Psychiatry News|
|Article Type:||Clinical report|
|Date:||Jun 1, 2011|
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