By Amy Norton
Researchers said the study results back up current guidelines on how to use the drugs, called erythropoietin-stimulating agents (ESAs).
Patients may still benefit from the medications because they reduce the need for blood transfusions to treat severe anemia, said Dr. Navdeep Tangri, senior researcher on the study.
"But this should close the book on the idea that these drugs help with exhaustion and improve patients' quality of life," said Tangri, an attending doctor at Seven Oaks General Hospital Renal Program in Manitoba, Canada.
However, one expert argued that while on average, that is true, some patients do feel better on the medications -- particularly younger, more active people.
People with chronic kidney disease often develop anemia, which hinders the blood's ability to transport oxygen. So doctors have long prescribed ESAs to boost blood levels of hemoglobin, the oxygen-carrying protein in red blood cells.
But in recent years, the drugs have come under closer scrutiny: Research has shown that using them to boost kidney patients' hemoglobin beyond a certain level -- around 11 grams per deciliter of blood -- can raise the risks of heart attack, stroke and blood clots.
So guidelines now recommend lower hemoglobin "targets," of no higher than 10 or 11. And the U.S. Food and Drug Administration says the only reason to prescribe the drugs to kidney disease patients is to curb the need for blood transfusions.
"They're not recommended for treating quality-of-life issues," said Dr. Jeffrey Berns, president of the National Kidney Foundation and a professor of medicine at the University of Pennsylvania.
Berns said the new study -- a review of 17 clinical trials -- "reinforces what's already out there." The new results were reported online Feb. 15 in the Annals of Internal Medicine.
In Berns' view, it makes sense that these medications would not change day-to-day life for many people with chronic kidney disease, especially those on dialysis. Patients are often older, have heart disease or other medical conditions, and are mostly sedentary.
"It's not realistic to expect that you'll improve their quality of life by raising their hemoglobin a little," Berns said.
But, he added, younger patients who are still physically active and have full-time jobs or families to take care of may feel the difference when their hemoglobin is at 9 instead of 11.
For their study, Tangri and his colleagues pooled results of clinical trials that tested ESAs and aimed for either relatively higher or lower hemoglobin targets. On average, patients in the higher-target groups got their hemoglobin to between 10 and 14, while those with lower targets had levels between 7 and 12.
Overall, the researchers found, patients with higher hemoglobin reported no bigger gains in quality of life.
There was some evidence that among patients not on dialysis, higher hemoglobin led to bigger improvements in their physical functioning and energy levels. But, Tangri said, the average differences did not appear "clinically meaningful."
He said the evidence does not support the idea that for certain patients, treatment should be "individualized" to reach a relatively higher hemoglobin level.
Berns disagreed -- in part, he said, because the studies have included few younger, healthier patients.
"One of the challenges we have is that a study, or a meta-analysis of studies, tells us about the average for a group of patients," Berns said. "That doesn't necessarily tell me what to do with the patient in front of me."
He said kidney disease patients on ESAs who don't feel better than they did before should ask their doctor whether it makes sense to stay on the drug.
It may, Berns said, since the drugs can help limit blood transfusions. That's a particular concern for patients awaiting a kidney transplant. Multiple transfusions can cause the immune system to generate antibodies with the potential to attack a donor kidney, he explained.
That still leaves the question of how to improve exhaustion and other quality-of-life issues for patients with chronic kidney disease.
"The search for effective options needs to continue," Tangri said. He added that those options could include diet changes and physical therapy, not just medication.
Berns is on the executive committee of a clinical trial funded by Amgen, maker of Epogen and Aranesp. Tangri is on the medical advisory board of Takeda Pharmaceuticals, which has marketed the anemia drugs Omontys and Feraheme.