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The newspaper of The Johns Hopkins University September 5, 2006 | Vol. 36 No. 1
Diagnosis, Referrals for Kidney Disease Fall Well Short of Need

By Jeff Ventura
Johns Hopkins Medicine

Results of a national study of 304 U.S. physicians in which mock patients' symptoms were presented for diagnosis suggest that a sizable percentage of primary care doctors probably fail to properly diagnose and refer patients with chronic kidney disease.

Their findings, reported in the August issue of the American Journal of Kidney Diseases, show that of 126 kidney specialists surveyed, 97 percent properly diagnosed chronic kidney disease, and 99 percent would have recommended specialized kidney care for the "patient." But only 59 percent of the 89 family physicians and 78 percent of 89 general internal medicine physicians fully recognized the signs and symptoms of the disease, and referrals to a nephrologist were made by only 76 percent of the family physicians and 81 percent of general internists.

"We, as physicians, can certainly do better," said L. Ebony Boulware, assistant professor of medicine at Johns Hopkins and lead author of the study. "Millions of people have kidney disease, but a substantial number may not have their disease recognized," she said. "Simply put, our study shows that primary care physicians are not recognizing kidney disease in high-risk patients as often as they should."

In the study, the Hopkins group asked the surveyed physicians to evaluate the medical files of a simulated patient being treated by a primary care doctor and suffering from progressive chronic kidney disease, a growing epidemic affecting an estimated 10 million Americans. The medical "record" contained clues to the condition indicating that, based on guidelines issued in 2000 by the National Kidney Foundation, the patient should be referred to a nephrologist for evaluation.

Chronic kidney disease is characterized by the progressive loss of renal function over a period of months or years. Signs include an abnormally low glomerular filtration rate, a standard measurement of renal health. The severe form of the disease, known as end stage renal disease, almost always requires dialysis, or kidney transplantation.

Boulware and her colleagues say early detection of chronic kidney disease is especially critical given that previous studies indicate that, for many high-risk patients, the progression of kidney disease can be markedly slowed if physicians prescribe appropriate therapies including blood pressure medications such as angiotensin-converting enzyme inhibitors or angiotensin II receptor-blocking agents.

Patients with hypertension, diabetes or a family history of kidney disease are at increased risk of kidney disease.

The survey was mailed to a randomly generated list of doctors between August 2004 and August 2005. The questionnaire described a hypothetical scenario in which a primary care doctor was evaluating a patient with moderately reduced kidney function progressing to severely reduced kidney function. After reading the scenario, which included detailed medical information about the patient, physicians were asked, "What is your estimate of the patient's kidney function?"

Physicians were also asked which diagnostic tests they would recommend administering to the patient, and whether or not they would refer the patient to a nephrologist "at this time."

The authors cited several potential reasons why family physicians and general internists may not always spot chronic kidney disease, such as lack of training to estimate kidney function and assess lab tests, lack of time and an "inadequate knowledge of CKD risk factors."

Although clinical evidence suggests that early referral to a nephrologist can result in a better outcome for the patient, it is unclear whether primary care physicians who are providing appropriate care to chronic kidney disease patients do any better or worse than specialists.

"Many of these primary care doctors are in absolutely the best position to diagnose and treat chronic kidney disease," said Neil R. Powe, professor of medicine at Johns Hopkins and one of the paper's co-authors. "These health-care professionals need to work with nephrologists to begin to eliminate the disagreement over how these patients should be treated and when they should be referred."

The study was funded by the National Kidney Foundation of Maryland, the Robert Wood Johnson Foundation and the National Institute of Diabetes and Digestive and Kidney Diseases.

The "random" list of doctors was generated from a list provided by the American Medical Association.


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