 | What Your Doctor Is Reading | | |
Update From the Medical Journals: September 2008
September 30, 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. Aggrenox, Plavix Offer Equal Protection For Stroke Patients Preventing a future stroke is an urgent priority for people who have already had a stroke or experienced temporary stroke symptoms (transient ischemic attack, or "TIA.") Experts agree that warfarin (Coumadin) is the best drug to reduce the chances of another stroke when a person has atrial fibrillation, an irregular heart rhythm. That's because it prevents clots from forming in the heart's atria and traveling to the brain. When atrial fibrillation isn't present, most experts recommend aspirin to prevent another stroke. But more powerful options are available. A previous study showed that a combination of aspirin and the blood-thinner dipyridamole (the combination pill Aggenox) was better than aspirin alone for lowering the stroke risk among people without atrial fibrillation. Another previous study showed that aspirin and clopidogrel (Plavix) were similar in stroke prevention. A new study published in the September 18 issue of the New England Journal of Medicine did a head-to-head comparison between Aggrenox and Plavix. Researchers followed 20,332 people with a history of a stroke for an average of 2 1/2 years. One group received Aggrenox twice daily. The other group received clopidogrel once a day. About 9% of the people in each group had had a recurrent stroke by the end of the study. The stroke rate was the same, and so was the chance of significant bleeding events. Does this study mean that Aggrenox and Plavix are tied for being the best medicine for preventing recurrent stroke? Yes, except for atrial fibrillation patients (who benefit more from warfarin) and for people who are trying to keep their health-care costs down. Aspirin will continue to be the first choice for patients who need to limit spending, because it costs less than $2 a month compared with $150 or more per month for Aggrenox or Plavix. If you take aspirin daily after a stroke, your odds of having a stroke in the subsequent three years will only be one out of six. This is not far from the protection of Aggrenox and Plavix — each lower the odds to about one out of eight. Also, aspirin has fewer side effects (particularly headache) than these other medications. Back to top Zetia, Vytorin Cholesterol Drugs Might Raise Cancer Risk Two new studies examined the possibility that two of the newest cholesterol medicines — ezetimibe (Zetia) and the combination drug ezetimibe/simvastatin (Vytorin) — might slightly raise the risk of dying from cancer. The New England Journal of Medicine published both studies on September 25, after they appeared in their online journal earlier in the month. The first study included 1,873 people. Half of them received Vytorin and half received a placebo (sugar) pill. The main purpose of the study was to see if taking Vytorin improved heart health. The researchers were disappointed to find it did not. But they were even more dismayed by an unexpected finding about cancers. The group taking Vytorin had more prostate cancers, digestive tract cancers, skin cancers, and other cancers than did the group taking the placebo pill. There were 39 deaths from cancer in the Vytorin group, compared with only 23 deaths among the people in the placebo group. Previous studies seemed to rule out the link between statin drugs, such as simvastatin, and cancer. Therefore, suspicion fell on ezetimibe, the other drug in Vytorin. In the second study, researchers analyzed data from ongoing trials to check out the suspected ezetimibe-cancer link. They reviewed the charts of more than 20,000 patients who had been treated with either ezetimibe or placebo for one to three years. There were 97 deaths from cancer in people who were treated with ezetimibe, and only 72 deaths from cancer in the other group. This was only a very slight difference, but experts do worry that the difference was seen after only the first few years of treatment. Concerns about cancer are not the only disappointing news to come out about ezetimibe this year. In April, a published study raised doubts about the value and safety of this drug with respect to heart disease. The ENHANCE trial was designed to see if a combination of ezetimibe and simvastatin (Vytorin) reduced the thickness of artery plaques (atherosclerosis) in the carotid artery better than simvastatin alone. Vytorin lowered LDL (the bad cholesterol) by 58% during two years of treatment compared with 41% with simvastatin alone. However, the artery plaques were slightly thicker, on average, among people who took ezetimibe/simvastatin compared with people who took just simvastatin. Some experts still think Zetia or Vytorin may be helpful for people who have very high LDL cholesterol. But there are growing worries that ezetimibe may do more harm than good in the end. Doctors and patients will probably cut back on using Zetia and Vytorin because of the slight cancer concerns, and also because there is also no clear proof that the drugs are beneficial. Do not stop either of these medicines without speaking to your doctor. Back to top More News in Brief - Virtual Colonoscopy Finds Most Polyps. Doctors recommend that you get screened for colon cancer starting at age 50. The most thorough test is a colonoscopy, which involves examining the entire colon with a camera that is at the end of a flexible cord-shaped "scope." A newer method of screening, called virtual colonoscopy (also called CT colonography), is now available. It involves filling the rectum with X-ray contrast dye through a tube. Then, a CT scan is done. If polyps are found, a colonoscopy is needed to remove them. Researchers published a study September 18 in the New England Journal of Medicine that compared virtual colonoscopy with colonoscopy. In the study, 2,600 people were given both tests. Virtual colonoscopy detected 9 out of 10 cancers that the standard test found. For high risk people or people who are known to form polyps, a colonoscopy is probably a more practical test to have done, because it can find polyps and remove them all in one procedure. Virtual colonoscopy every five years or so is probably a fine choice for people at average risk for colon cancer. The test is not yet available at every medical center, but over time, we will see more testing centers offer it.
- CDC Recommends Testing More People for Hepatitis B. On September 18, the U.S. Centers for Disease Control and Prevention (CDC) expanded their recommendation for who should bet tested for hepatitis B infection: All pregnant women, babies who are born to mothers with hepatitis B, household contacts and sex partners of people who are infected, people with HIV, people who were born in Asia or Africa (the infection is very common there), men who have sex with men, injection (IV) drug users, people who are about to take drugs that could suppress the immune system, and people with abnormal liver blood tests. Hepatitis B infection affects between 800,000 and 1.4 million Americans, and it leads to death from cirrhosis or liver cancer in 2,000 to 4,000 people each year. Hepatitis B can be a silent infection, but it can cause slow deterioration in the function of your liver. It is a treatable virus.
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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