 | What Your Doctor Is Reading | | |
Update From the Medical Journals: July 2007
July 30, 2007  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. Antidepressants May Thin Bones Millions of people who take antidepressant medicines may be at risk for thinning bones. Two studies published in the June 26 issue of the Archives of Internal Medicine raised this concern when they found a link between drugs known as selective serotonin reuptake inhibitors, or SSRIs, and loss of bone strength. The most commonly used SSRI medications include Prozac, Zoloft, Celexa, Lexapro and Paxil. The first study followed 2,722 women, most of whom were over age 65, for about 10 years. Women who took SSRIs lost bone in their hips at about twice the rate as women who didn't take SSRIs. In the second study of 5,995 men who were also older, those who took SSRI drugs had an average bone density that was nearly 4% lower at the hip and nearly 6% lower at the spine than that of non-SSRI users. Neither study is proof that the drugs caused the bone loss. The researchers considered an alternative explanation for their results: Does depression itself lead to thinner bones? To answer this question, the researchers looked to see if bone density was lower among people in the studies who took other types of antidepressants. They did not find a link. They also considered whether differences in exercise activity or in the severity of depression might explain lower bone density measurements in the patients who were taking antidepressants. These two factors also did not appear to be related to the bone loss. Only the SSRI group of medicines showed a clear association with bone loss. The same receptors in the brain that bind to serotonin are also found in bones. To maintain a constant bone strength, the building up of new bone tissue and tearing down older bone tissue need to occur with a perfect rhythm. The researchers suspect that bone effects occur because drugs that change serotonin activity might tip this careful balance. In light of these studies, patients and their doctors will need to think carefully about how long to treat depression with SSRIs. Back to top Leg-Vein Clots Occur During or After a Hospital Stay It's common for blood clots to form in the deep veins of the legs when people are bedridden because blood circulation is not as brisk as usual. This kind of clot is called a "deep venous thrombosis" or DVT and can cause pain, leg swelling and complications. The most dangerous complication of DVT is a pulmonary embolus, which is a blockage of blood flow to one or more areas of your lungs. It occurs when a clot in the leg breaks off or dislodges, sending solid debris through your bloodstream and into the lung arteries. In a study published in the July 23 issue of the Archives of Internal Medicine, researchers analyzed information from 1,897 people who had a leg or lung clot. They found that about three out of four people were living in their homes (they were not hospitalized) when they developed symptoms and were diagnosed with DVT. However, more than half of these individuals had been hospitalized or had had surgery in the preceding three months, and more than 50% experienced DVT within one month of leaving the hospital. The risk was greatest during the first two weeks after leaving the hospital. Anti-clotting medication can prevent clots after surgery or when you're immobile. The drug of choice is usually twice-daily injections of heparin. Many of the people who formed DVTs had not received this protective medicine during their hospital stay, even though it's the standard of care for people in the hospital who are immobile or recovering from surgery. This study will hopefully prompt doctors to give heparin to a larger number of hospitalized patients. It will also lead to discussions about whether heparin injections should be continued — perhaps for a month or more — after a person leaves the hospital. Back to top How Many Americans Are Alcoholic? The National Epidemiologic Survey on Alcohol and Related Conditions has concluded that 30% of people in the United States have gone through a period of alcohol abuse or alcohol dependence in their lifetimes. The results of the survey, conducted by the National Institute on Alcohol Abuse and Alcoholism, were based on in-person interviews with 43,093 people ages 18 and older. The findings were published in the July issue of Archives of General Psychiatry. The survey used "textbook" criteria to define alcohol abuse and alcohol dependence. Individuals who reported any one of the following features were considered to be alcohol abusers. Reporting three or more features in the same year resulted in a diagnosis of alcohol dependence: - A larger number of drinks is needed before you begin to feel the effect of alcohol. (This is called tolerance.)
- Withdrawal symptoms occur when you stop drinking.
- At times you drink more heavily than you planned.
- You have made unsuccessful efforts to cut down.
- You spend a lot of time drinking or recovering from drinking.
- You have missed job or recreational activities due to your drinking.
- You know alcohol has contributed to a health problem or mental health problem that you have, but you keep drinking anyway.
According to the results, one out of eight Americans have been alcohol dependent at some time during their lives. One out of every twenty-six people (3.8%) have been alcohol dependent during the past year. An additional 5% reported alcohol "abuse" during the past year. The most high-risk age for alcohol disorders to begin is age 19. On average, for people who reported alcohol dependence, signs of dependence appeared by age 22. Only one out of four people who were alcohol-dependent received any formal treatment (by a doctor or program). If they did receive treatment, most people surveyed did not get treatment until they had been having alcohol problems for eight years or longer. This survey is a wake-up call to doctors and families to be more aware of alcohol abuse problems, and to offer help sooner. A surprisingly high proportion of adults are harmed by alcohol. Back to top Sports Physicals Should Now Include Screening Test for Sickle Cell Trait The National Athletic Trainers' Association (NATA) has for the first time suggested that sports physicals should include a blood test for "sickle cell trait." People who have the trait should have minor modifications made in their exercise participation. The association made their recommendation in a consensus statement that was shared at their June 27 annual meeting and published on their website. The recommendations are more cautious than the ones published by the American Academy of Pediatrics (AAP) Committee on Sports Medicine and Fitness and those typically used by doctors who do sports physicals. In the AAP guidelines, people who have known sickle cell trait don't need to modify their athletic participation, and screening for the condition is not routinely recommended. Sickle cell trait is related to sickle cell disease, but it is much more common and is a less frequent cause of symptoms. People with sickle cell trait have one normal gene and one "sickle cell gene," while people with sickle cell disease have two abnormal genes. Sickle cell trait doesn't usually cause symptoms. However, heat, dehydration and exposure to high altitude can cause red blood cells to temporarily change from a round shape to the sickle shape of a quarter-moon, if a person has one sickle cell gene. As a result, red blood cells can't carry oxygen nor travel smoothly through small capillaries. This causes cramping, weakness, muscle breakdown, and changes in the body's metabolism that can be fatal. During the last seven years in the United States, nine deaths after collapse during exercise have been blamed on sickle cell trait. The NATA recommends that people with sickle cell trait avoid mile sprint runs or serial sprints, take longer rest periods between bursts of intensive exercise and gradually build-up to intense repetitions. Eight to ten percent of blacks in the U.S. have sickle cell trait. All 50 states require some form of newborn testing for sickle cell trait — either in all newborns or in high-risk (black) individuals. To check for sickle cell trait during a sports physical, a doctor could review newborn testing records if they are available, or use a blood test to newly test for the condition. Back to top More News in Brief - Older Diabetes Drugs Are Still the Best. On July 16, the Annals of Internal Medicine website published a systematic review of diabetes drugs. Their purpose was to identify how well oral diabetes medications worked to lower blood sugar, and which medicines were most likely to cause side effects. Researchers compared 216 studies as well as unpublished data that were provided by the U.S. Food and Drug Administration and pharmaceutical companies. Most of the medicines that are used to treat diabetes lower blood sugar by similar amounts when their highest doses are compared. The medications that came out on top in this analysis were metformin (Glucophage) and second-generation sulfonylurea medicines such as glipizide (Glucotrol) and glimepiride (Amaryl). These are all older drugs for treating diabetes so their cost is also lower than most other diabetes drugs. Metformin was associated with modest weight loss and mild improvement in LDL cholesterol, in addition to lowering blood sugar effectively. Metformin caused more diarrhea and other abdominal symptoms compared with sulfonylurea drugs, but fewer low blood-sugar episodes. For subscribers, Consumer Reports has also created a consumer guide of diabetes drugs based on these study results.
- Radiation from Cardiac CT Scan Poses Cancer Risk. The July 18 issue of the Journal of the American Medical Association (JAMA) includes a study evaluating radiation-exposure risk from a relatively new test. New ways to check for coronary artery disease are in development, and one test that has appeal to some experts is a computed tomography scan (CT scan) of the coronary arteries called a CT coronary angiogram (CTCA). This scan can show narrowing of coronary arteries. It can also detect calcium, indicating that there are cholesterol deposits in the arteries. Most of the available machines that can be used for this test expose the patient to a significant dose of radiation. To estimate the risk from this radiation, researchers used calculations to predict how often lung cancer or breast cancer would be expected to occur after this amount of radiation exposure. The researchers estimate that a single CT coronary angiogram done at age 60 would cause cancer in one out of every 715 women and one out of every 1,911 men. This risk is small, but it will need to be considered by doctors and patients who are choosing between this test and other tests (such as treadmill tests, stress echocardiogram tests, or coronary angiogram) that can evaluate coronary artery health.
- Restless Legs Syndrome Has Genetic Basis. In the July 19 issue of the New England Journal of Medicine researchers revealed that certain genes are associated with restless legs syndrome, a condition that causes leg movements at night and is a common cause of interrupted sleep. Medications can improve restless legs syndrome. The gene variations that were associated with the condition are very common. Having one of the genes does not mean that you need medication, if you are sleeping well without it. Genetic testing is not recommended for people who have restless legs symptoms, since it is not necessary to confirm the diagnosis. Nonetheless, knowing that the condition has a genetic basis may help with continued drug development.
Back to top Mary Pickett, M.D. is a lecturer for Harvard Medical School and an assistant professor of medicine at Oregon Health & Science University. At OHSU, she is a director of student programs and she oversees teaching of students and medical residents. She practices general internal medicine in Portland, Ore.
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