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Kidney screening program uses new GFR equation.

NEW YORK -- Boosting patient awareness and use of a new equation for measuring glomerular filtration rate are showing early signs of being the cornerstones to the prevention of chronic kidney disease among people at risk for the disease, according to preliminary results from the National Kidney Foundation's nationwide screening initiave.

The Kidney Early Evaluation Program (KEEP) has enrolled 150,000 people so far, making it the nation's largest perpetual chronic kidney disease screening program, according to Dr. Joseph Vassalotti, chief medical officer of the National Kidney Foundation and a faculty member at Mount Sinai School of Medicine, New York.

The point is to identify "individuals in the community with kidney disease along with the risk factors that go with it," said Dr. George Bakris of the University of Chicago Medical Center and a former KEEP principal investigator. All of the participants have some stage of kidney disease or hypertension and are referred to the registry by physicians. Enrollment is voluntary and participants complete a questionnaire and undergo a medical evaluation that includes standard panels plus testing for calcium, phosphorus, and parathyroid hormone. The program does not accept people who have had a kidney transplant or are on dialysis, he said.

Under the program, a new method for estimating glomerular filtration rate (eGFR), known as the Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation, has been used. This equation is more accurate in determining kidney function than is the Modification of Diet in Renal Disease (MDRD) study equation, said Dr. Lesley Stevens of Tufts Medical Center, Boston. "The use of the CKD-EPI equation more accurately reflects measured GFR and results in a lower prevalence of eGFR below 60 mL / min per 1.73 [m.sup.2]," said Dr. Stevens, a KEEP committee member. As a result, there are fewer false positives and "ultimately, fewer tests and lower costs," she said.

According to Dr. Stevens, the equation has been validated in two clinical studies (Am. J. Kidney Dis. 2010;55:648-59 and Am. J. Kidney Dis. 2010;55:660-70).

One of the goals of KEEP is to determine factors that help slow the slide into chronic kidney disease, said Dr. Vassalotti. "Multiple trials on systolic blood pressure show that untreated hypertension results in a loss of 10-12 mL/min per 1.73 [m.sup.2] eGFR a year," he said. "In individuals with blood pressure in the target range, the annual loss is approximately 2-3 mL/min per 1.73 [m.sup.2]."

Managing blood pressure early in kidney disease is critical because as eGFR declines, hypertension becomes more difficult to control, Dr. Vassalotti said. Thus, self-reported hypertension is one of the qualifiers for KEEP enrollment, he said. He cited early data from KEEP that showed prevalence, awareness, and treatment of hypertension increased with stage of chronic kidney disease, but that didn't necessarily translate to control with severe disease. Among those with stage 3 disease, only 82% were undergoing treatment, compared with 92% of those with stage 4 disease. However, 38% of the stage 3 group had systolic blood pressure below 140 mm Hg, while only 35% of the stage 4 group did (Am. J. Med. 2008;121:332-40).

KEEP data have shown an uptick in overall blood pressure control, from 45% at the initial screening to 49% at rescreening, Dr. Vassalotti said. The project involves merging data with the National Death Index and the United States Renal Data System to track survival and chronic kidney failure outcomes, respectively. Future goals include additional data links with Medicare Parts B and D to gain clarity on morbidity and medication use, he said.

Patient awareness is the cornerstone of hypertension management, noted Dr. Adam Whaley-Connell of the University of Missouri.

"Awareness has a very important role in not only understanding blood pressure control, especially in the context of the early stages of kidney disease, but in improving kidney related patient outcomes," he said. However, he noted that awareness of kidney disease, particularly in its early stages, "is alarmingly low."

He noted that KEEP data on aware ness reflect that of National Health and Nutrition Examination Survey and other CKD cohort studies: Only about 5% of those with stages 1-3 are aware of their disease. "Roughly 95% of individuals entering into the screening program are unaware they have chronic kidney disease," Dr. Whaley-Connell said.

KEEP enrollees with cardiovascular disease had a keener awareness of the risks of kidney disease, he said.

"While awareness may be triggered by cardiovascular disease, those unaware in the earlier stages of kidney disease are particularly vulnerable to poor risk factor control and increased risk for mortality and progression to end-stage renal disease," Dr. Whaley-Connell said.

"I think any general practitioner seeing patients needs to pay attention to eGFR," Dr. Bakris said. "If the patient has stage 2 disease and an eGFR of 60-80 mL/min per 1.73 [m.sup.2] now, especially with the CKDEPI equation, the next question out of his mouth should be, "Do you have a family history of kidney disease?'"


Major Finding: KEEP data have shown an uptick in overall blood pressure control among patients with early-stage kidney disease or hypertension, from 45% at the initial screening to 49% at rescreening.

Data Source: Preliminary results from the National Kidney Foundation's screening initiative.

Disclosures: KEEP is funded by Amgen, Abbott, Siemens, Astellas, Genzyme, Fresenius Medical Care, Pfizer, Nephroceuticals, and the LifeScan unit of Johnson & Johnson. Panel participants disclosed affiliations with a variety of device and pharmaceutical companies.

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Title Annotation:KIDNEY DISEASE; glomerular filtration rate
Author:Kirkner, Richard M.
Publication:Family Practice News
Geographic Code:1USA
Date:Jul 1, 2011
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