Persistent Use of Beta Blockers Associated With Heart Failure Survival
Allen LaPointe NM, Zhou Y, Stafford JA, Hernandez AF, Kramer JM, Anstrom KJ. Association between mortality and persistent use of beta blockers and angiotensin-converting enzyme inhibitors in patients with left ventricular dysfunction and coronary artery disease. Am J Cardiol. 2009;103:1518-1524.
By Maggie De Pano, Duke Clinical Research Institute Communications
Researchers at the Center for Research and Education in Therapeutics (CERT) at Duke Clinical Research Institute (DCRI) found that the use of beta blockers—a class of drugs used to manage high blood pressure and protect the heart following a heart attack—is associated with higher survival rates among patients with chronic heart failure. However, there doesn't seem to be a difference between evidence-based beta blockers and non-evidence-based beta blockers in this regard.
On the other hand, researchers found no association between the use of angiotensin-converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARB)—a group of drugs used to treat high blood pressure and congestive heart failure-and higher survival rates.
These findings were published in the June 1, 2009 issue of the American Journal of Cardiology. DCRI CERT investigator Nancy M. Allen LaPointe, PharmD, associate professor of medicine, led the study.
Heart failure takes place when cardiac output is insufficient for the body's needs. This may occur when the cardiac output is low (often referred to as "congestive heart failure"), or when the body's requirements for oxygen and nutrients increase and outstrip what the heart can provide (this can happen in persons with anemia, vitamin B deficiency, or an excess of thyroid hormones in their body).
The researchers evaluated the longer-term use of beta blockers and ACE inhibitors/ARBs in patients with left ventricular systolic dysfunction (where the left ventricle of the heart pumps 40 percent or less of the blood inside it out with every heartbeat) and coronary artery disease who had undergone a cardiac catheterization procedure from April 1994 to December 2005. Patient data was extracted from the Duke Databank for Cardiovascular Disease (DDCD), a clinical database containing medical conditions and treatments for all patients who have undergone a cardiovascular procedure at Duke since 1969.
LaPointe's team gave the patients two follow-up surveys to fill out and then categorized them into one of four categories: persistent use (patients who reported using the medication in both surveys), previous-use (reported medication use only in the first survey), new use (reported medication use only in the second survey), and non-use (didn't report medication use in either survey).
Of the 3,187 patients identified for beta blocker analysis, 1,339 (40%) were classified as persistent use. The risk of death was significantly lower with persistent use versus no use, with a 0.73 hazard ratio in favor of the first group, as well as with new use versus no use, at a 0.82 hazard ratio, also in favor of the first group. A hazard ratio of one means that there is no difference in survival between the two groups. A hazard ratio of greater than one or less than one means that survival was better in one of the groups.
However, the researchers found no statistically significant difference in the risk of death associated with the persistent or new use of evidence-based beta blockers and the persistent or new use of non-evidence-based beta blockers.
Meanwhile, of 3,166 patients identified for ACE inhibitor/ARB analysis, 1,347 (42.5 %) were classified as persistent use. There was also no statistically significant association between risk of death and persistent use, previous use, and new use, compared to no use of this group of drugs.
Other DCRI researchers who contributed to the study include Yi Zhou, MS; Judith A. Stafford, MD; Adrian F. Hernandez, MD; Judith M Kramer, MD, MS; and Kevin J. Anstrom, PhD.
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