Diabetic kidney disease on the rise in US

Issue: July 2011

During the past 2 decades, the prevalence of diabetic kidney disease in the United States has increased in direct proportion to the prevalence of diabetes itself.

Using data from the National Health and Nutrition Examination Survey, researchers found that the estimated number of people with diabetic kidney disease in the United States at any given point of time increased from 3.9 million during 1988-1994 to 5.5 million during 1999-2004 to 6.9 million during 2005-2008.

“Diabetic kidney disease has become more prevalent in the US population over the past 2 decades and will likely contribute increasingly to health care costs and mortality,” Ian H. de Boer, MD, MS, and colleagues at the University of Washington, Seattle, wrote in the Journal of the American Medical Association.

The researchers examined trends in the prevalence of diabetic kidney disease in the United States and changes in disease manifestations among patients with diabetes during the past 20 years. To do this, they analyzed data from the NHANES 1988-1994 (n=15,073); NHANES 1999-2004 (n=13,045); and NHANES 2005-2008 (n=9,588). Those with diabetes were defined by an HbA1c level of at least 6.5%, use of glucose-lowering medications, or both (n=1,431 in NHANES 1988-1994; n=1,443 in NHANES 1999-2004; n=1,280 in NHANES 2005-2008). Diabetic kidney disease was defined as diabetes with albuminuria (ratio of urine albumin to creatinine ≥30 mg/g), impaired glomerular filtration rate (<60 mL/min/1.73 m²), or both.

The prevalence of diabetic kidney disease in the US population was 2.2% in 1998-1994 and increased to 2.8% in 1999-2004 and to 3.3% in 2005-2008. The researchers calculated a demographically adjusted increase in diabetic kidney disease of 18% from 1988-1994 and 34% from 1988-1994 to 2005-2008.

However, the researchers found that “improvements in reaching therapeutic targets in diabetes management have not translated into a decline in diabetic kidney disease,” de Boer, who is assistant professor of medicine in the division of nephrology at the Kidney Research Institute, said in a University of Washington press release.

During the study period, the proportion of those taking glucose-lowering medications increased from 56.2% to 74.2%. Additionally, the use of renin-angiotensin-aldosterone system inhibitors increased from 11.2% to 40.6%, as did the use of lipid-lowering medications, primarily statins, from 8.9% to 50.2%.

The researchers discovered that the prevalence of impaired glomerular filtration rate increased from 14.9% in 1988-1994 to 17.7% in 2005-2008. The prevalence of albuminuria decreased from 27.3% to 23.7% during these time periods; however, this change was not statistically significant. There were also decreases in mean HbA1c levels and mean systolic and diastolic blood pressure.

“Among persons with diabetes, clinical manifestations of diabetic kidney disease shifted to include more impaired glomerular filtration rate, but the prevalence of any diabetic kidney disease did not change despite increased use of diabetes-related medications,” the researchers said.

One thing that did change was the clinical manifestation of the disease, the researchers said. Patients aged 65 years or younger were less likely to have diabetic kidney disease than in past years.

“The results of our research don’t suggest that standards of diabetes care for controlling blood sugar levels, high BP and cholesterol should be changed,” de Boer said in the release. “What the findings suggest is that these treatments alone are not doing an effective job of reducing diabetic kidney disease, and researchers need to find additional ways to do that.”

For more information:

de Boer IH. JAMA. 2011;305:2532-2539.

Disclosure: Dr. de Boer reports no relevant financial disclosures.

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