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
"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
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
Patients with hypertension, diabetes or a family
history of kidney disease are at increased risk of kidney
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
"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
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
The "random" list of doctors was generated from a
list provided by the American Medical Association.