Kidney disease tied to mental impairment

Menopausal women with chronic kidney disease have lower scores on tests of mental proficiency (cognitive function) than those without chronic kidney disease, according to a new study.

"Since chronic kidney disease is common, especially among the elderly, these findings suggest chronic kidney disease is an important risk factor for cognitive impairment," Dr. Manjula Kurella told Urine Health.

Kurella, of the University of California, San Francisco, and colleagues assessed data for more than 1,000 women enrolled in the Heart Estrogen/Progestin Replacement Study to investigate the effect of kidney function on cognition. All subjects had established coronary artery disease at study entry.

The participants (average age of 66.7 years) underwent a battery of six cognitive function tests. Chronic kidney disease was classified as mild, moderate or severe based on the estimated glomerular filtration rate (eGFR), according to the team's report in the American Journal of Kidney Diseases.

The results showed a significant association between eGFR and impairment in global cognition, executive function, language and memory. This association was not influenced by patient age, race, education level, lifestyle factors, stroke, and other laboratory test variables.

"While persons with kidney failure on dialysis were known to have an increased risk of dementia and milder forms of cognitive impairment, the increased risk of cognitive impairment among persons with milder degrees of kidney failure (i.e. chronic kidney disease not yet on dialysis) was not appreciated," Kurella commented.

SOURCE: American Journal of Kidney Diseases, January 2005.