Diabetic kidney disease more prevalent in US

Diabetic kidney disease (DKD) is a common complication of diabetes and the leading cause of chronic kidney disease in the developed world. Approximately 40 percent of persons with diabetes develop DKD, which also accounts for nearly half of all new cases of end-stage renal disease (ESRD) in the United States. "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," according to background information in the article the authors write.

Ian H. de Boer, M.D., M.S., of the University of Washington, Seattle, and colleagues examined trends in the prevalence of DKD in the United States and changes in disease manifestations among persons with diabetes over the past 2 decades. The study included data from the Third National Health and Nutrition Examination Survey (NHANES III) from 1988-1994 (n = 15,073), NHANES 1999-2004 (n = 13,045), and NHANES 2005-2008 (n = 9,588). Participants with diabetes were defined by levels of hemoglobin A 1c of 6.5 percent or greater, use of glucose-lowering medications, or both (n = 1,431 in NHANES III; 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 or greater), impaired glomerular filtration rate (less than 60 mL/min/1.73 m 2 estimated using the Chronic Kidney Disease Epidemiology Collaboration formula), or both.

The researchers found that the prevalence of DKD in the U.S. population was 2.2 percent in 1988-1994, 2.8 percent in 1999-2004, and 3.3 percent in 2005-2008, with the demographically adjusted increase in DKD prevalence being 18 percent from 1988-1994 to 1999-2004 and 34 percent from 1988-1994 to 2005-2008. The estimated numbers of persons with DKD in the U.S. at any given point in time increased from 3.9 million during 1988-1994 to 5.5 million during 1999-2004 to 6.9 million during 2005-2008.

The proportion of persons with diabetes taking glucose-lowering medications increased from 56.2 percent to 74.2 percent and the use of renin-angiotensin-aldosterone system inhibitors increased from 11.2 percent to 40.6 percent. The prevalence of impaired GFR increased from 14.9 percent in 1988-1994 to 17.7 percent in 2005-2008. The prevalence of impaired albuminuria decreased from 27.3 percent to 23.7 percent during these time periods, but this was not statistically significant.

"In conclusion, 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. Among persons with diabetes, clinical manifestations of DKD shifted to include more impaired GFR but the prevalence of any DKD did not change despite increased use of diabetes-related medications," the authors write.