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Update From the Medical Journals: August 2008
August 29, 2008  By Mary Pickett, M.D.
Harvard Medical School What's the latest news in the medical journals this month? Find out what your doctor is reading. Medicines Are As Good As Angioplasty for Most Cases of Angina Balloon angioplasty with the placement of a stent can relieve symptoms of angina (chest pain or pressure) for people who have coronary artery disease. But medications are just as helpful — and less risky — for people with stable or slowly changing symptoms. This was the conclusion of an important study published August 14 in the New England Journal of Medicine. The study included 2,287 people who had chest pain. Patients were randomly assigned to one of two groups. The first group received angioplasty as well as medicines that can relax arteries, relax the heart rate, improve cholesterol and prevent blood clots. With the exception of a blood thinner (clopidogrel or Plavix) that is needed after angioplasty, the second group got just the medicines. Patients in both groups had their medicines adjusted until angina symptoms were reduced. After only three months of treatment, half (53%) of patients in the medicines-plus-angioplasty group and nearly half (42%) of patients in the medicines-only group no longer had symptoms. After three years of treatment, no differences were seen between the two groups regarding symptoms, survival or overall health. Patients were allowed to change from the medications group to the medicines-plus-angioplasty group, if their symptoms were improving too slowly for their satisfaction. Twenty-one percent of the people in the medicines-only group decided to have angioplasty. Medicines that were used in this study are some of the most commonly prescribed drugs for angina: Aspirin, metoprolol (Toprol), amlodipine (Norvasc), isosorbide mononitrate (Imdur), simvastatin (Zocor) and either lisinopril (Prinivil, Zestril) or losartan (Cozaar). People in the stent group also took clopidogrel to prevent clots from forming inside the stent. The fact that the two treatment groups had nearly the same outcomes means that people with stable symptoms of angina have two very good options for treating coronary artery disease. Angioplasty has become much more common over the last thirty years as the techniques have been improved. This study tells us we may be using angioplasty more often than we should. There is a risk of complications with this procedure. So we should reserve it for cases where it can make a meaningful difference to a patient's quality of life. This study did not include people who showed signs of a heart emergency, such as the first signs of a heart attack, chest pain that occurred with no exercise trigger, or chest pain occurring with a minimal exercise trigger. The best treatment for these problems (which are all considered "acute" or "unstable" coronary syndromes) is angioplasty because it lowers the risks of heart attack and death. Also, people who had severe symptoms of angina also seem to benefit from angioplasty somewhat more than they benefit from medicines alone. Back to top Sleep Apnea Increases Risk for Dying Prematurely Sleep apnea is a common problem that interrupts a person's sleep. Researchers have found that it may increase the risk of dying prematurely by two to three times. The results of the study were published in the August 1 issue of Sleep. Researchers followed the health and survival of 1,522 randomly selected adults ages 30 to 60 for an average of 13.8 years. At the start of the study everybody had an overnight study to diagnose problematic sleeping patterns. "Sleep apnea" refers to episodes during sleep when a person briefly stops breathing. If you have the most common type of sleep apnea, your tongue and throat muscles become extremely relaxed during sleep. They collapse together, so that air can't get into your lungs. When your oxygen level drops, your adrenaline level surges. This helps you to wake up and recover your breathing. However, it also raises blood pressure and increases your risk for heart problems. People who are obese are more likely to have sleep apnea. The researchers took health conditions, such as obesity (measured by body mass index) and heart disease into consideration when they analyzed their results. They found that these health conditions could not account for the increased risk for death that was linked to sleep apnea. Sleep apnea was an independent risk for dying young. People who had untreated sleep apnea were at greatest risk for dying prematurely. They were four times more likely to die during the years of the study and were five times more likely to die specifically from heart disease. The most common way to treat sleep apnea is with a "CPAP" (continuous positive airway pressure) mask and machine, which is worn at night to help keep the air passages open by blowing light air pressure. It has been estimated that 12 to 18 million Americans have sleep apnea. Many of these people are unaware that they have the condition. If a bed partner comments that you snore frequently, if you are particularly sleepy during daytime or if you have frequent headaches in the morning, consider having a conversation with your doctor about testing for sleep apnea. Back to top Gene Patterns Reveal the Biology of Bipolar Disorder Bipolar disorder (also called bipolar affective disorder or manic depression) is a type of depression that causes extreme mood swings. It is increasingly clear that the origins of this illness are biological. According to a study published online August 17 by the journal Nature Genetics, scientists may have unlocked a large part of the mystery behind the disease when they identified two abnormal genes linked to bipolar illness. At times, the person with bipolar disorder is severely depressed. During "manic" episodes, however, the person will be very excited, active or irritable. Bipolar disorder can run in families. Thus, doctors guessed many years ago that genetics might be behind this disease. The latest study was the largest genetic study ever done on bipolar disorder. Researchers combined gene data that had been collected in smaller studies. The combined study included a total of 10,596 people. Of these, 4,387 had bipolar disorder. Comparing these groups let scientists see what gene variations were closely linked with bipolar disease. Both of the genes affect the way our bodies build structures called "ion channels" on the surface of nerve cells. Ion channels are the gates used by charged particles as they surge in and out of cells. Sodium and calcium are two of these ions. Opening and closing of ion channels is what causes a nerve cell to "fire." This means that it sends an electrical signal to the next cell. Problems can occur in this process. Nerve cells may not fire easily. Or they may be "excitable" and fire too easily. These problems can lead to unhelpful patterns of brain signaling. Unstable nerve activity probably is what causes the symptoms of bipolar disorder. So far, it is not practical to use genetic testing to diagnose bipolar disorder. Even though these two abnormal genes are associated with the condition, they are not perfect predictors of the disease. There are other genetic changes that might trigger the problem. Understanding the biology of bipolar disorder shows us that there are good reasons why some drugs treat bipolar disorder better than others. For bipolar disease, the best ("first line") treatments are known as mood stabilizers. The most famous and most helpful of these medicines is lithium. This is a salt, similar to other sodium salts. Lithium affects the way that sodium travels through ion channels. Many of the other mood stabilizers used to treat bipolar disorder help to prevent nerves from firing in unpredictable ways. Examples are valproic acid (Depakote), carbamazepine (Tegretol) and lamotrigine (Lamictal). These drugs were first used to control or prevent seizures in people who have epilepsy. Traditional antidepressant drugs are less likely to help for bipolar disorder. Back to top More News in Brief - More Americans Infected with HIV Than Previously Estimated. U.S. health officials from the Centers for Disease Control and Prevention reported that they had underestimated the number of Americans who become infected by the AIDS virus (acquired immunodeficiency syndrome virus) each year. The revised estimate was published in the August 3 issue of the Journal of the American Medical Association. Improved accuracy of blood testing and correct statistical methods were the reasons the estimate was revised. The new estimate is 40% higher than previously reported. There were 56,300 new cases of HIV (human immunodeficiency virus) infections in the U.S. in 2006.
- People With HIV Are Living Longer. On a brighter note, the July 26 issue of The Lancet reported encouraging statistics about how treatment has changed life expectancy for people with HIV. Analyzing outcomes for more than 40,000 patients who had been diagnosed with HIV, researchers made this prediction: Anyone who was 20 years old between 2003 and 2005 and who began treatment with a recommended combination of HIV antiviral medicines when he or she was first diagnosed can expect to live to an average age of 69, with continued treatment. Compared with HIV diagnoses that were made in the years 1996-1999, that is a gain of more than 13 years.
- Men Over 75 Should Not Have Screening PSA Tests. The U.S. Preventive Services Task Force (USPSTF) makes recommendations about screening tests. The job of this organization is to review tests, analyze evidence and provide updates to doctors and patients about which tests are sensible for preventive health care, and which tests are not. In the August 5 Annals of Internal Medicine, the USPSTF published new guidelines about prostate cancer screening. Men older than 75 should not be screened for prostate cancer using the PSA (prostate specific antigen) blood test. This test can identify many cases of prostate cancer, but not all prostate cancer leads to noticeable illness. In addition, every positive PSA test causes psychological stress. Identifying and treating prostate cancer can cause complications, such as urinary incontinence (wetting), bowel control problems, impotence or surgical complications – even death. The possible harms of testing men older than 75 outweigh the benefits, when you average the testing experience among men over 75.
Back to top Mary Pickett, M.D. is an Associate professor at Oregon Health & Science University where she is a primary care doctor for adults. She supervises and educates residents in the field of Internal Medicine, for outpatient and hospital care. She is a Lecturer for Harvard Medical School and a Senior Medical Editor for Harvard Health Publications.
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