Combination Test Helps Predict End-Stage Renal Disease

Assessment of kidney function by measuring two different factors, glomerular filtration rate (GFR) and urinary albumin levels helped to determine which chronic kidney disease (CKD) patients will develop end-stage renal disease. This combination test could help physicians identify patients at high risk of serious kidney trouble and allow them to intervene at an early stage.

There is a high prevalence of CKD worldwide, but relatively few individuals with the disease develop ESRD. Physicians and scientists have looked for ways to identify which patients will progress to ESRD in order to target patients most in need of extensive treatment, and help establish clinical guidelines and public health plans for treating patients with CKD.

Stein Hallan, M.D., Ph.D. at St. Olav University Hospital (Trondheim, Norway), and his colleagues recently conducted a study to see if combining two of the tests commonly used to measure kidney function might help predict ESRD. One test measures an individual's estimated glomerular filtration rate (eGFR is a measure of the volume of fluid filtered by the kidneys), and the other measures the amount of albumin (the predominant protein in blood) that is excreted in urine. A high urinary albumin level indicates a rapid rate of kidney disease progression, and a low eGFR indicates an advanced stage of disease.

Data from 65,589 adults who participated in the population-based Nord-Trøndelag Health (HUNT 2) Study were analyzed and 124 individuals developed ESRD after more than 10 years of follow-up. Combining urinary albumin and eGFRs results identified more than 65% of patients who would develop this condition. Other factors such as hypertension, diabetes, smoking, obesity, and cardiovascular disease did not provide any additional information that could be used to predict who would develop ESRD.

"We provide clear evidence... that reduced eGFR should always be complemented by information on urine-albumin to yield optimal prediction of the risk of progression to ESRD," said Dr. Hallan. He added that combining these measurements might also help reduce the number of patients referred to specialists without losing the ability to detect future ESRD cases.

The study appeared in the Journal of the American Society of Nephrology (JASN) in April 2009.

St. Olav University Hospital

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