Update From the Medical Journals: August 2011 - What Your Doctor Is Reading - Harvard Commentaries

What's the latest news in the medical journals this month? Find out what your doctor is reading.

Depression May Increase Strokes in Women
New Clot-Prevention Drugs Offer Another Option for Treating Atrial Fibrillation
More News in Brief: Soy Does Not Help Relieve Hot Flashes; Benefits of Deep Brain Stimulation For Parkinson Symptoms Last for 10 Years; New Gene Therapy For Chronic Lymphocytic Leukemia (CLL) Looks Promising

Women who are depressed have a higher risk of stroke than other women. This new observation comes from a study that monitored the health of 80,574 women for six years. The study is part of the ongoing Nurses' Health Study. It was published online August 11 in the journal Stroke.

The women were 54 to 79 years old. At the time the study began, none of them had a history of stroke. About 22% of them were depressed or had been depressed in the past.

During the next six years, there were 1,033 strokes. The stroke rate was 29% higher in women with depression or a history of depression compared with women with no depression history. The increased risk was not explained by other risk factors for stroke, which were also assessed in the study.

Women who were taking antidepressant medicines had 39% more strokes than women who were not taking antidepressant medicines. The researchers were not able to say whether the drugs caused the extra risk. The women taking medication may have more severe depression.

Overall this study raised more questions than it answered. We do not know the reason depression is associated with a higher stroke risk. There are several theories. Depression may lead to chemical changes in the brain. Also, depression is more common in women who have health problems such as vascular (artery) disease. Finally, depressed people tend to eat a less healthy diet and to exercise less.

It is helpful to identify and treat depression. We do not yet know whether treatment of depression can improve a person's risk for other medical conditions.

Atrial fibrillation is a heart rhythm condition that slows the blood flow in the left atrium of the heart. This can allow a blood clot to form. If the blood clot travels it can cause a stroke. People who have atrial fibrillation commonly use clot-prevention drugs (also called anticoagulants or blood thinners) to lower their risk for stroke.

Rivaroxaban is the newest drug to prevent clots. The New England Journal of Medicine published findings online on August 10 concerning the safety and benefits of rivaroxaban. In this study, 14,264 patients were randomly assigned to receive either rivaroxaban or the anticoagulant drug warfarin (Coumadin). The stroke rate was 1.7% per year for the rivaroxaban group, and 2.2% for the warfarin group. This was not a significant difference.

In February 2011, the American College of Cardiology, the American Heart Association and the Heart Rhythm Society updated the guideline for preventing stroke in people with atrial fibrillation. A new clot-prevention drug called dabigatran (Pradaxa) was included as a treatment option. Rivaroxaban is a very similar drug to dabigatran. It's very likely that the next version of the guideline will include rivaroxaban. Warfarin, dabigatran and rivaroxaban are strong clot-prevention drugs; aspirin provides mild stroke prevention.

Warfarin is the drug that is traditionally used for stroke prevention. But it's a tricky drug to use. It requires close monitoring with blood tests at least every three weeks to make sure the dose is correct. Certain drugs and foods can temporarily cause warfarin to either be less effective than needed, or more hazardous. Even with frequent blood tests, only about 60% of patients don't need their doses adjusted at each check.

Dabigatran and rivaroxaban, unlike warfarin, do not require frequent blood tests for monitoring. But it is not clear that these will be better therapies. While they save on laboratory costs, they are very expensive. (Dabigatran costs about $10 per day, and rivaroxaban will probably have a similar cost).

Some experts are also worried that it may be more difficult to treat overdose or bleeding complications from dabigatran and rivaroxaban. That's because these side effects can't easily be reversed in an emergency. If warfarin has made the blood too thin, doctors can use vitamin K or neutralizing "binders" to reverse the effect.

Soy Does Not Help Relieve Hot Flashes. A study funded by the National Institutes of Health found that soy did not help reduce menopausal hot flashes or improve bone health. The study appeared in the August 8 issue of the Archives of Internal Medicine. Most women — 80% — have symptoms of hot flashes as they enter menopause. Taking estrogen with or without progesterone can relieve these symptoms. But estrogen treatment increases the risk of breast cancer, blood clots and stroke. Soy is chemically similar to estrogen. So researchers wondered if soy could be as beneficial as estrogen but without the risks.

In this study, 248 women in their first five years of menopause were randomly assigned to get a soy pill or placebo pill each day. The amount of soy in the pill was double the amount typically consumed in an Asian diet. The women's symptoms were monitored for two years. They also had bone density tests to track bone health. There were no differences in the number of hot flashes or in bone density between the two groups. It does not seem that soy (by prescription or by diet sources) is useful in menopause.

Benefits of Deep Brain Stimulation for Parkinson's Symptoms Last for 10 Years. A controversial therapy for treating symptoms of Parkinson's disease is deep brain stimulation. Surgeons place electrodes into specific areas of the brain. The electrodes increase nerve signals in areas that otherwise have lower activity in Parkinson's disease. This treatment was expected to improve motor function. The long-term effects of the treatment, however, have not been studied until now.

For 10 years, researchers followed 18 patients who had the procedure done. The results were reported online by the Archives of Neurology on August 8. These researchers looked at ease of movement, severity of tremors and muscle stiffness. Each of these functions were evaluated with and without medication, and with and without the deep brain stimluator turned on. One year, 5 years and 10 years after the stimulator was implanted, patients did best when treatment included both the stimulator and medications. Posture, gait and balance all seemed to get worse over time with or without treatment with the deep brain stimulator.

Brain surgery for implantation of a deep brain stimulator does seem to offer Parkinson's patients some benefit even 10 years after surgery. But it can't improve every symptom of Parkinson's disease. Deep brain stimulation has only been studied in a small number of patients.

New Gene Therapy For Chronic Lymphocytic Leukemia Looks Promising. Gene therapy may put chronic lymphocytic leukemia (CLL) into remission. The early results based on three patients were published August 10 by the New England Journal of Medicine and Science Translational Medicine.

Researchers isolated T-cells from the patients' blood so that these cells could be altered. New genes were inserted into the DNA of these cells in a laboratory. Then the cells were infused back into the patients. The T-cells helped the patients' own immune systems fight the cancer more effectively. One year later, two of the three patients seemed to be cancer-free. The third patient had a partial response. It is not clear how long this type of gene therapy might be able to keep patients with CLL in remission from their cancer, since long-term studies have not been done. Based on these initial results, the technique offers a very exciting new approach to treating CLL and potentially other cancers.

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.