 | What Your Doctor Is Reading | | |
Update From the Medical Journals: February 2009
February 27, 2009  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. Early X-rays or Imaging Tests Are Not Helpful for Back Pain According to an analysis published February 7 in The Lancet, X-rays or imaging tests of your spine are not helpful for new low back pain. Unless your doctor finds signs that suggest you might have a serious medical problem, the information from computed tomography (CT) or magnetic resonance imaging (MRI) scans doesn't appear to improve pain, functioning, quality of life or treatment costs. Researchers combined data from six back pain studies and reviewed the outcomes of 1,804 patients. The studies compared patients who had an immediate X-ray, CT or MRI scan at the initial back-pain evaluation with patients who had no imaging tests. At 3, 6 and 12 months after the first doctor visit, patients who had an immediate scan or X-ray were no better off in terms of pain, function, quality of life, satisfaction or cost. There were no signs among the patients of a serious medical problem, such as a spine infection, cancer, compression of the spinal cord or a fracture. If one of these problems is suspected, a CT, MRI or X-ray is recommended. Signs of a serious medical problem include: Recent weight loss; unexplained fever; older age or thin bones (osteoporosis); weakness in the feet or legs; a traumatic injury; previously diagnosed cancer; and an increased risk for infection due, for example, to injection drug use or low immunity. It's clear from this study that people with new back pain aren't likely to benefit from imaging tests unless there is a reason ("red flag") to suspect a serious problem. If you have back pain that doesn't improve in the first six weeks despite treatment with physical therapy, then a scan or X-ray might be a good idea to help re-direct your treatment. Back to top Genetic Testing Can Help Predict Right Dose of Warfarin Warfarin (Coumadin), a blood thinner, is an important treatment for people who have blood clots in the leg or lung, or have atrial fibrillation (an abnormal heart beat). Warfarin requires careful monitoring to find the right dose for each person. This is because people metabolize the drug differently depending on their genes. Genetic testing can be used to predict who will require a higher or lower dose of warfarin. But until now, doctors didn't have a clear way to calculate doses based on genetic tests. On February 19, researchers published an analysis in the New England Journal of Medicine that provided such a guide by matching different genetic patterns to suggested doses of warfarin. This analysis looked at data from 5,700 patients who were already on a stable dose of warfarin. They divided patients into different groups based on results of genetic tests for the "CYP2C9" and "VKORC1" genes. After some trial and error, they were able to come up with dosing calculations for each different gene pattern. The calculations also took into account a patient's age, weight, race and gender. Their "formula" did not work perfectly — two out of three patients would still need some dose adjustment after starting warfarin using the calculation. Still, the formula did seem to predict the right dose more often than doctors can without the information from genetic tests. Before doctors can confidently rely on this strategy, researchers will use the genetic tests to guide their warfarin dosing for 1,200 patients over the next three years. The patients will be closely watched to make sure that they do not have more side effects, such as bleeding, with the new dosing strategy. After this follow-up study, it is likely that genetic testing will help determine the starting dose of warfarin for all patients. Back to top More News in Brief - Blood Test May Predict Postpartum Depression. Measuring a protein called "placental corticotrophin-releasing hormone" (pCRH) during the 25th week of pregnancy may predict the women who are most likely to develop postpartum depression. The study appeared in the February issue of Archives of General Psychiatry. The protein was measured in 100 pregnant women. Three out of four women with a high pCRH level later developed postpartum depression. Only about one out of every 20 women with a low level of pCRH developed depression. It may be helpful for women to have this test to plan her post-delivery care. This discovery may eventually lead to a new way we could prevent or treat postpartum depression.
- Home-Cooked Meals Are Becoming "Supersized." Restaurant-portion sizes have increased, which has contributed to obesity. In a letter published February 17 in the Annals of Internal Medicine, two researchers showed that portion size has also increased over time for home-cooked meals. They compared the seven editions of The Joy of Cooking cookbook, published between 1936 and 2006. Only 18 recipes have been included in every edition. In updated editions, these "signature" recipes have increased the proportion of calorie-dense ingredients (for example, sweeteners). When researchers analyzed food ingredients independently from the serving size, they found that the calorie density of these recipes had also increased by 37.4%. Newer editions have also upgraded the portion size for many recipes. Over the last 70 years, the average number of calories per serving has increased by 63%. About half of this increase has occurred since the 1996 edition. To reverse the trend towards obesity, we will need to reduce calories that we consume both in and out of the home.
- Discovery Boosts Hopes for New Flu Treatment. According to scientists, we may encounter a flu epidemic during the next decade. That's why a new weapon against flu is needed. On February 22, the journal Nature Structural & Molecular Biology reported in its online edition that scientists have identified an antibody that can neutralize a broad range of influenza viruses. If this antibody can be mass-produced (a process that is usually possible) and passes safety testing, it could be a promising new prevention or treatment for flu some day.
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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