Kidney Disease Increasing in U.S.

By Steven Reinberg
HealthDay Reporter
Wednesday, November 7, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

TUESDAY, Nov. 6 (HealthDay News) -- The number of Americans with chronic kidney disease is on the rise, and diabetes and high blood pressure linked to obesity appear to account for most of the increase, a new study suggests.

"When we looked at how common kidney disease was, we found that it was more common than previously appreciated," said lead researcher Dr. Josef Coresh, a professor of epidemiology at Johns Hopkins University.

The prevalence of chronic kidney disease among U.S. adults has risen in a decade from 10 percent to 13 percent, according to the report in the Nov. 7 issue of the Journal of the American Medical Association.

The aging population is part of the reason for the increased prevalence of kidney disease, Coresh said. But, he added, "There are also substantially higher rates of obesity and diabetes. These are both risk factors for kidney disease."

In addition, more people have high blood pressure, which is often uncontrolled, Coresh noted. High blood pressure can also damage the kidneys.

For the study, Coresh's team collected data on 15,488 people in the 1988 to 1994 National Health and Nutrition Examination Surveys (NHANES). The researchers then compared these people with 13,233 people who participated in the 1999 to 2004 NHANES survey.

The researchers compared the levels of chronic kidney disease between the two groups. To establish the presence of kidney disease, Coresh's group used measures of excess protein in the urine and the glomerular filtration rate, which measures the amount of fluid filtered by the kidneys.

The prevalence of protein in urine and a reduction in the glomerular filtration rate both increased from the first to the second survey. Overall, the prevalence of chronic kidney disease increased from 10.0 percent in the 1988-to-1994 survey to 13.1 percent in 1999 to 2004 survey, the researchers found.

The increase in the prevalence of kidney disease appears due to more cases of high blood pressure and diabetes being diagnosed, and much of that is caused by obesity. This increase in obesity seems to explain the increase in extra protein in the urine but only part of the decrease in the glomerular filtration rate, Coresh said.