Anemia Linked To Heart Failure Complications
Low hemoglobin levels are a predictor of increased risk of death and complications among heart failure patients, according to a report in Circulation: Journal of the American Heart Association.
Hemoglobin (Hgb) is the major substance in red blood cells, and its level indicates the blood’s ability to carry oxygen throughout the body.
“If you are a heart failure patient and your hemoglobin drops, then you are at a greater risk of having problems," says Dr. Inder S. Anand, the study’s lead author, and professor of medicine at the University of Minnesota Medical School and director of the Heart Failure Program, VA Medical Center, Minneapolis, Minn.
"What remains unclear, however, is the ideal level of hemoglobin to be achieved in patients with heart failure,” he says.
Researchers say one of the causes of anemia may be related to iron deficiency in heart failure patients because of malabsorption, nutritional deficiencies, and impaired metabolism.
Excess fluid retention may also contribute to anemia in heart failure patients.
Researchers do not know if anemia worsens heart failure or if it is a marker of heart failure severity, or what effect raising hemoglobin will have on the heart’s function.
“It is important to pursue hemoglobin’s role in the risk of death and complications in heart failure patients,” Dr. Anand says.
“The lifetime risk for developing heart failure for men and women at age 40 is one in five," he says. "If 30 percent to 60 percent of these people are at higher risk for death and complications because of low hemoglobin, we might have an opportunity to treat these patients.
“Treatment for anemia is relatively simple, with iron supplements, multivitamins, or drugs," Dr. Anand notes. "However, we do not yet know if treatment is the best strategy and what the goals of treatment should be.”
Studies have shown that low hemoglobin, which may result in anemia, is more common among patients with heart failure than it is among people in the general population. As many as 25 percent to 60 percent of heart failure patients have anemia, defined as hemoglobin less than 12 grams/deciliter (g/dL) in women and 13g/dL in men.
“Studies have shown that if you have anemia and heart failure, your risk of death and complications [is] increased appreciably - with as much as 30 percent to 60 percent additional risk of death and hospitalization from heart failure,” says Dr. Anand.
To study the association between anemia and mortality risk, the researchers used a database on 5,002 patients enrolled in the Valsartan Heart Failure Trial, a study evaluating the high blood pressure medication valsartan.
At the beginning of the study, researchers took a complete blood cell count, and repeated these measurements at regular intervals up to 24 months. Of the patients enrolled in the heart failure study, 23 percent were anemic. Anemic patients tended to be older, have diabetes, and to have worse heart failure.
The researchers found that the group of patients with the largest average decreases in Hgb over 12 months (defined as an average decrease of 1.6 g/dL, from 14.2 to 12.6 g/dL) experienced 47 percent more hospitalizations and 60 percent more deaths, compared to those in the group that exhibited an insignificant (0.10 g/dL) change in hemoglobin during 12 months.
The researchers report that an increase in Hgb was associated with a 22 percent lower death rate in patients with anemia, compared to 21 percent without anemia, at the start of the study.
Patients who had anemia at the start of the study or whose Hgb decreased during the study had worse heart failure and an associated elevation of several other risk factors for heart disease.
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American College of Cardiology
American Heart Association
Centers for Disease Control and Prevention (CDC)
Circulation: Journal of the American Heart Association
National Heart, Lung, and Blood Institute (NHLBI)
National Institutes of Health (NIH)
National Library of Medicine
National Women's Health Information Center
Stroke: Journal of the American Heart Association
US Health and Human Services
Persons with prehypertension are at much higher risk of heart attack and heart disease, according to a study published in Stroke: Journal of the American Heart Association.
“If we were to eliminate prehypertension, we could potentially prevent about 47 percent of all heart attacks,” says the study’s lead author Dr. Adnan I. Qureshi, professor and director of the Cerebrovascular Program in the Zeenat Qureshi Stroke Research Center at the University of Medicine and Dentistry of New Jersey.
Normal blood pressure is defined as lower than 120/80 millimeters of mercury (mm Hg).
Prehypertension is defined as systolic blood pressure between 120 and 139 and/or diastolic pressure between 80 and 89 mm Hg.
Systolic pressure is the force in the arteries when the heart beats and diastolic pressure is the force when the heart is at rest.
About 59 million people in the United States are prehypertensive.
Hypertension is defined as blood pressure 140/90 mm Hg or higher.
“There is a gray zone, where you are not hypertensive but your blood pressure is not normal either,” Dr. Qureshi says.
More than a year ago, a national committee coined the term “prehypertension” for this gray area.
But until this study, Dr. Qureshi notes, physicians and the public knew little about what this term meant.
Researchers examined existing data from the Framingham Study and found that a prehypertensive person is more than three times more likely to have a heart attack and 1.7 times more likely to have heart disease than a person with normal blood pressure.
They did not find a significantly increased risk of stroke among those with prehypertension.
“This is somewhat surprising, but it may be related to the small number of stroke events in the study,” Dr. Qureshi says.
“The differential effect in this gray zone may be mediated through factors other than blood pressure, such as insulin resistance,” he says.
“While we classically recommend lifestyle modifications such as weight control, regular physical activity, and changes in diet for people with prehypertension, these findings raise the question of whether we should treat prehypertensive patients more aggressively.
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