A new diagnostic strategy that includes three markers may significantly improve the detection and treatment of kidney disease, according to findings published online in the Journal of the American Medical Association.
The investigators, who also presented their findings recently at the World Congress of Nephrology in Vancouver, found that a panel of three tests for kidney disease (creatinine, cystatin C, and urine albumin-to-creatinine ratio [ACR]) was more accurate in identifying kidney disease and predicting risk of kidney failure and death than the creatinine test alone, which is the current standard diagnostic test.
“Based on creatinine levels, about 14 million people in the United States are currently classified as having CKD,” said investigator Carmen Peralta, MD, Assistant Professor of Medicine at the University of California in San Francisco. “We estimate that testing for cystatin C and albumin in the urine would reclassify about five million of these people as being without increased risk for kidney disease, and would more accurately predict the risks of kidney failure and death for the other nine million.”
The researchers studied 26,643 subjects with an average age of 65 years. These subjects were participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. REGARDS is a national longitudinal study designed to identify factors that contribute to excess stroke mortality in the so-called “stroke belt” across the mid-southern United States, as well as factors that contribute to excess stroke risk among African Americans. Subjects were followed from January 2003 to June 2010.
Dr. Peralta and her colleagues found that 16% of study subjects who were not shown to have chronic kidney disease (CKD) based on creatinine levels were correctly identified by tests for cystatin C and ACR as having CKD. Conversely, among subjects identified as having CKD through elevated creatinine, 24% were found not to have CKD as shown by measurements of cystatin C and ACR.