"Five million or so people have been diagnosed with, and are living with, congestive heart failure," said Dr. Kirkwood F. Adams Jr. "Because of changes in the age of our population, that number is predicted to double within a decade, and as a result, both the economic burden and the magnitude of congestive heart failure in terms of sickness and death will continue to grow. In the past, anemia has been a neglected aspect of the condition, and that needs to change if we're going to serve patients well."

Raising hemoglobin levels through treatment with drugs that mimic erythropoietin might help patients by improving cardiac function and improving their limited ability to exercise, the physician said. Researchers already have made significant progress in treating congestive heart failure in recent years, particularly with such drugs as beta-blockers.

"But up to 40 percent of patients can't take beta-blockers long-term, and so seeking additional treatments is still important," Adams said.

Adams noted that the poor blood flow associated with congestive heart failure contributes to various systemic changes, including impaired kidney function, and, often, anemia.

"We recognized this anemia in the past, but many physicians questioned whether it needed to be treated if it was only moderate," Adams said. "Recent studies, however, have suggested that anemia adversely affects heart function not only in dialysis patients but in congestive heart failure patients as well."

Several clinical trials have indicated that depression of hemoglobin level, even to a limited degree, is linked to increased mortality of hospitalized myocardial-infarction patients.

"Then clinicians began looking at this in congestive heart failure and began finding that anemia-reduced hemoglobin was an independent predictor of adverse outcomes," Adams said.

Two recent small and preliminary studies have further shown that hemoglobin level increased in patients treated with erythropoietin and that those patients' ability to exercise improved, he said. One study even suggested that the drug could cut the time that patients spent in the hospital.

Dr. Adams' university serves as the coordinating center for a U.S. nationwide heart failure registry, UNITE-HF, composed of 15 academic medical centers that collect and pool patient data for study. Working with a drug company and registry data, Adams and colleagues have begun studying the effects of anemia on patients' physical activity and fatigue, the effect of hormones on anemia, and patient quality-of-life issues.

"This focus on anemia is new, and it is definitely worth investigating because we believe it may make a difference with many congestive heart failure patients, and results so far have been encouraging," he said.