Chronic Kidney Disease Increasing in the U.S.


BALTIMORE, Nov. 7 -- The estimated prevalence of chronic kidney disease in the U.S. has swelled over 10 years from 10% to 13%, according to a survey.
Action Points
Explain to interested patients that diabetes, hypertension, and obesity are risk factors for chronic kidney disease which in turn increases the risk of cardiovascular disease and kidney failure.
The increase has been partly fueled by an increase in diabetes, hypertension, and obesity, Josef Coresh, M.D., Ph.D., of Johns Hopkins, and colleagues, reported in the Nov. 7 issue of the Journal of the American Medical Association.
Rates of kidney failure leading to dialysis and transplantation in the U.S. have increased from 1988 to 2004, the researchers noted. Whether there has been a change in the prevalence of earlier stages of kidney disease during this period has been uncertain, the researchers said.
Chronic kidney disease is now recognized as a common condition that elevates the risk of cardiovascular disease as well as kidney failure, they said, although awareness of kidney disease in the general public is low. It is estimated that by 2015, there will be 136,000 patients with incident end-stage renal disease and a prevalence of 712,000 patients with kidney disease.
The investigators compared the prevalence, stages, and severity of chronic kidney disease in a cross-sectional analysis of two National Health and Nutrition Examination Surveys (NHANES 1988-1994 and NHANES 1999-2004). During the period between the surveys, the U.S. population became older and included a smaller proportion of non-Hispanic whites.
The nationally representative samples of noninstitutionalized Americans 20 or older included 15,488 in the earlier survey and 13,233 in the later survey.
Chronic kidney disease prevalence was determined by persistent albuminuria and decreased estimated glomerular filtration rate (GFR).
Persistence of microalbuminuria (>30 mg/g) was estimated from repeat-visit data in NHANES 1988-1994. The GFR was estimated using the abbreviated Modification of Diet in Renal Disease Study equation re-expressed to use standard serum creatinine.
The prevalence of both albuminuria and decreased GFR increased from 1988-1994 to 1999-2004, the researchers said.
The prevalence of chronic kidney disease stages one to four increased from 10.0% (95% confidence interval, 9.2%-10.9%) in 1988 to 1994 to 13.1% (95% CI: 12% to 14.1%) in 1999-2004 with a prevalence ratio of 1.3 (95% CI: 1.2 to 1.4).
The prevalence estimates of the four stages for chronic kidney disease in 1988-1994 and 1999-2004, respectively, were:
1.7% (95% CI: 1.3% to 2.2%) and 1.8% (95% CI: 1.4% to 2.3%) for stage 1.
2.7% (95% CI: 2.2% to 3.2%) and 3.2% (95% CI: 2.6% to 3.9%) for stage 2.
5.4% (95% CI: 4.9% to 6%) and 7.7% (95% CI: 7% to 8.4%) for stage 3.
0.21% (95% CI: 0.15% to 0.27%) and 0.35% (95% CI: 0.25% to 0.45%) for stage 4.
A higher prevalence of diagnosed diabetes and hypertension and higher body mass index (BMI) explained the entire increase in prevalence of albuminuria but only part of the increase in the prevalence of decreased glomerular filtration rate.
Estimation of GFR from serum creatinine has limited precision yet a change in mean serum creatinine accounted for some of the increased prevalence of chronic kidney disease, the investigators said.
Although the shift in age distribution was less pronounced in individuals older than 60 in whom kidney disease is more common, the prevalence of self-reported diabetes and hypertension increased. Similarly there was an increase in the mean BMI and the proportion of individuals who were overweight and obese, all risk factors for chronic kidney disease.
Overall, the increase of chronic kidney disease from 10% to 13.1% in the 10 years between surveys was largely attributed to the increase in obesity, diagnosed diabetes, and hypertension, and was only slightly explained by the aging of the population, the researchers said.
These increasing rates of diabetes and hypertension may lead to higher rates of complications and eventually kidney failure requiring dialysis or transplantation.
In fact, the age- and sex-adjusted incidence of end-stage renal disease in the U.S. increased 42% from 1991 to 2001. Even with progress in treating kidney failure, the growing prevalence of diabetes and the aging of the population will result in a progressive increase in the number of patients with kidney failure.
Earlier stages of kidney disease accounted for most of the individuals in this study, the researchers noted, but because these individuals have a higher risk of cardiovascular morbidity and mortality than their risk of kidney failure, management of cardiovascular risk factors in this group is also critical.
Study limitations included reliance on an estimation of GFR, rather than direct measurement. The persistence of albuminuria was also estimated from limited data and was assumed to be the same in different age and subgroups.
The high prevalence of chronic kidney disease overall, and particularly among older individuals and those with hypertension or diabetes, suggests that kidney disease needs to be a central part of future public health planning, the investigators concluded.
No financial disclosures were reported. The research for this study was supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases. Co-author Elizabeth Selvin Ph.D., was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases.
Primary source: Journal of the American Medical AssociationSource reference: Coresh J, et al "Prevalence of Chronic Kidney Disease in the United States"JAMA 2007; 298: 2038-2047.