US Prevalence of Diabetic Kidney Disease Rising

Laurie Barclay, MD

June 27, 2011

June 27, 2011 — The US prevalence of diabetic kidney disease (DKD) is rising, according to the results of cross-sectional analyses reported in the June 21 issue of JAMA.

"Diabetes is the leading cause of kidney disease in the developed world," write Ian H. de Boer, MD, from the University of Washington in Seattle, and colleagues. "Over time, the prevalence of [DKD] may increase due to the expanding size of the diabetes population or decrease due to the implementation of diabetes therapies."

Using cross-sectional analyses of the Third National Health and Nutrition Examination Survey (NHANES III, from 1988 to 1994; n = 15,073), NHANES 1999-2004 (n = 13,045), and NHANES 2005-2008 (n = 9588), the investigators assessed changes over time in US prevalence of DKD. In NHANES III, there were 1431 persons with diabetes, defined by levels of hemoglobin A1c of 6.5% or higher, use of glucose-lowering medications, or both. There were 1443 persons with diabetes in NHANES 1999-2004, and 1280 in NHANES 2005-2008.

Persons with diabetes were considered to have DKD if they had albuminuria, defined as a ratio of urine albumin to creatinine of 30 mg/g or higher, and/or impaired glomerular filtration rate, defined as a rate less than 60 mL/min/1.73 m2, estimated using the Chronic Kidney Disease Epidemiology Collaboration formula. The prevalence of albuminuria was adjusted to estimate persistent albuminuria.

In the US population, DKD prevalence was 2.2% (95% confidence interval [CI], 1.8% - 2.6%) in NHANES III, 2.8% (95% CI, 2.4% - 3.1%) in NHANES 1999-2004, and 3.3% (95% CI, 2.8% - 3.7%) in NHANES 2005-2008 (P < .001 for trend). The prevalence of DKD rose in direct proportion to the prevalence of diabetes, but DKD prevalence among those with diabetes did not change.

Use of glucose-lowering medications among persons with diabetes increased from 56.2% (95% CI, 52.1% - 60.4%) in NHANES III to 74.2% (95% CI, 70.4% - 78.0%) in NHANES 2005-2008 (P < .001), whereas use of renin-angiotensin-aldosterone system inhibitors increased from 11.2% (95% CI, 9.0% - 13.4%) to 40.6% (95% CI, 37.2% - 43.9%) during the same time (P < .001).

Among persons with diabetes, impaired glomerular filtration rate increased from 14.9% in NHANES III (95% CI, 12.1% - 17.8%) to 17.7% (95% CI, 15.2% - 20.2%) in NHANES 2005-2008 (P = .03). The prevalence of albuminuria also decreased from 27.3% (95% CI, 22.0% - 32.7%) to 23.7% (95% CI, 19.3% - 28.0%), respectively, but this was not statistically significant (P = .07).

"Prevalence of DKD in the United States increased from 1988 to 2008 in proportion to the prevalence of diabetes," the study authors write. "Among persons with diabetes, prevalence of DKD was stable despite increased use of glucose-lowering medications and renin-angiotensin-aldosterone system inhibitors."

Limitations of this study include the absence of institutionalized persons in the NHANES sample, the underrepresentation of persons who are ill with advanced DKD, and uncertainty in albuminuria prevalence estimates.

"DKD has become more prevalent in the U.S. population over the last 2 decades and will likely contribute increasingly to health care costs and mortality," the study authors conclude. "Among persons with diabetes, clinical manifestations of DKD shifted to include more impaired [glomerular filtration rate] but the prevalence of any DKD did not change despite increased use of diabetes-related medications."

The National Center for Research Resources, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, and Satellite Healthcare's Norman S. Coplon Extramural Grant Program supported this study. One of the study authors reported that all honoraria and consulting fees from serving on the Shire Scientific Advisory Board on Outcomes Studies in Hemodialysis Patients and the Nephrion/Cytopheryx Medical Advisory Board are donated to the Kidney Research Institute at the University of Washington. In addition, money is paid to his institution (University of Washington) for his consulting work for Genzyme, Lilly, and Thrasos. The other authors have disclosed no relevant financial relationships.

JAMA. 2011;305:2532-2539. Abstract