Could Anemia Of Chronic Disease Be A Good Thing?
An analysis article in the Canadian Medical Association Journal suggests that anemia of chronic disease may be a beneficial, adaptive response to underlying disease, rather than a negative effect of the illness, and therefore efforts to treat it may be doing more harm than good.
Anemia of chronic disease is common in patients with conditions such as cancer, heart failure, kidney failure and infection. Affected patients have low levels of red blood cells and therefore low hemoglobin, despite having normal levels of iron.
“There has long been an assumption that anemia of chronic disease is harmful because patients with anemia tend to fare worse,” said author Dr. Ryan Zarychanski. “We suggest that this anemia is actually part of the body’s effort to heal itself, so you would expect to see it in the sicker patients. As such, correcting the anemia with blood transfusion or drugs cancels out our own body’s beneficial and adaptive response. Preventing a sick person from being slightly anemic may be analogous to preventing a cold person from shivering or a hot person from sweating. These are necessary adaptive responses to stress in our environment.”
Dr. Zarychanski is a critical care physician and hematologist affiliated with the Ottawa Health Research Institute, the University of Ottawa, The Ottawa Hospital and CancerCare Manitoba. Co-author Dr. Donald Houston is a hematologist and associate professor affiliated with the University of Manitoba and CancerCare Manitoba.
In the article, the authors review previous research suggesting that the level of anemia seen in chronic disease is probably not low enough to impact oxygen delivery to tissues, and it may actually prevent the growth of bacteria and cancer and improve blood flow. They also review a number of randomized clinical trials that have shown that treatment of anemia with drugs or blood transfusion is associated with an increased risk of death.
“We believe there is enough evidence to advocate restraint in the treatment of mild to moderate anemia of chronic disease,” said Dr. Zarychanski. “We also believe that there is a great need for further research in this area and we hope that by raising these questions we will stimulate that.”