MONDAY, June 21, 2004 (HealthDayNews) -- Doctors too often are not recognizing the subtle signs of potentially life-threatening kidney problems in older patients hospitalized for heart disease, a study finds.
Although the medical tests given to heart patients on admission include one for kidney function, the results usually are given in a hard-to-interpret form that causes trouble to be overlooked, said Dr. William M. McClellan, professor of medicine at Emory University and lead author of a paper on the study in the July issue of the Journal of the American Society of Nephrology.
The study analyzed admissions of nearly 15,000 Georgia Medicare patients, average age 74, hospitalized for either heart attacks or congestive heart failure. It found moderately reduced kidney function in 52 percent of the heart attack patients and 60 percent of those with heart failure, in which the heart progressively loses the ability to pump blood.
Yet the existence of kidney problems was recognized in only 20 percent of those patients, the study found. The gap exists primarily because the tests results list only blood levels of creatinine, a molecule whose levels depends on kidney function. It takes skilled interpretation of the creatinine level to determine whether kidney function is below normal, McClellan said, and most doctors don't do it.
The U.S. government is aware of the problem and is working with companies that market laboratory tests to make the kidney data available in more usable form, said Dr. Josephine P. Briggs, director of the Kidney, Urology and Hematology Division of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Meanwhile, McClellan said, failure to recognize kidney problems in heart patients can have serious consequences.
"Most important, frequently when you deal with patients with kidney disease you must change medication dosages, modify X-ray procedures, and otherwise account for kidney disease," he said. "Second, when you don't recognize kidney disease you don't look for complications like anemia, malnutrition, and bone disease that can go untreated. By treating them, impaired quality of life can be avoided.
"The third problem is that you don't do the things you should do to slow the progression to end-stage kidney disease."
The consequences showed up in the Georgia study. Patients with kidney problems were more likely to be re-hospitalized within a month and were more likely to die within a year -- three times more likely for patients with heart failure, the journal report said.
The NIDDK has started a National Kidney Disease Educational Program to increase the awareness of physicians of the importance of measuring kidney function in heart patients, Briggs said. A key part of that effort is to have kidney data presented in terms of the glomerular filtration rate (GFR), which is a direct indication of kidney function, she said.
"We are suggesting that commercial laboratories should do more to present data on GFR," Briggs said. About 10 to 15 percent of laboratories now give results in terms of GFR rather than creatinine levels, she said, and talks with some major companies are on the verge of producing results.
"We hope that in a year or two, a number of large companies will be doing that." Briggs said.
You can get A-to-Z information about kidney and related diseases from the National Institute of Diabetes and Digestive and Kidney Diseases.