Update From the Medical Journals: February 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.

High-Fiber Diet Predicts Longer Life
Implantable Monitor Reduces Hospital Stays for Heart Failure
More News in Brief: Expanded Combination of Antibiotics Now Recommended for Ulcer Treatment, New Clot-Prevention Drug Approved for Atrial Fibrillation, Americans Should Eat Less Salt, and Researchers Focus on Protein That Changes Heart Healing

People who eat a high-fiber diet live longer, according to a study published online February 14 by the Archives of Internal Medicine. Researchers surveyed the dietary habits and health of 388,000 men and women over age 50 for nine years. People were divided into one of five groups based on how much fiber they ate regularly. The group with the highest fiber consumption had 22% fewer deaths during the study years compared with the group with the lowest fiber intake. This difference was found after taking into account differences in weight, educational background, smoking and common chronic diseases.

Fiber is a part of fruits, vegetables, grains (bread, cereal) and beans that we can't digest. It has no calories and just passes out of us. But fiber carries with it important vitamins and minerals. It moves our digestion along at a faster pace, helping us to eliminate other non-digestible things (like carcinogens) more quickly.

In this study, fiber appeared to be good for heart health and the immune system, and was even helpful in lung disease. The best fiber seemed to be from whole grain foods. It is a great idea to increase the number of fiber-containing foods in your diet. The men in the "high-fiber" group in this study averaged 29 grams a day; the women averaged 26 grams a day. But change your fiber slowly, because your digestive system will need to gradually adjust.

Heart failure can limit a person's physical activity or cause occasional fatigue. During a flare-up, heart function worsens. This can lead to leg swelling, breathing distress and sometimes a hospital stay. When an episode occurs, ajusting heart medicines such as diuretics can help people to improve. These adjustments work best when the flare-up is identified quickly.

Now, promoters of a surgically implanted monitor say their device can alert doctors early in a heart failure episode. Their study, published online February 9 by Lancet, randomly assigned 270 patients with symptomatic heart failure to either receive the device or not. The study then compared the two groups. Remarkably, those with the device had 30% fewer hospital stays in the first 6 months of the study, and 39% fewer stays for those patients who were tracked longer.

The implantable monitor (called a "hemodynamic" monitor) is still experimental. It is designed to detect a change in pressure that occurs in the early stages of a heart failure flare. This monitor measures pressure where the right side of the heart empties blood into the arteries of the lungs. A high pressure suggests that the left side of the heart is falling behind in its work. The monitor is a little larger than a silver dollar. It is surgically placed in the chest wall near the left shoulder — similar to a pacemaker. A wire about 12 inches long from the device goes through the wall of a large vein in the chest, into the superior vena cava, and into the right side of the heart. A person can use a telephone-like device to "download" information from the device, which can be transmitted to a central analyzing location. If a pressure change is detected, a doctor can make changes to a patient's medicine before the patient has noticed symptoms.

This implantable system depends on patients regularly downloading their data in order to get benefits. In my experience, heart failure patients who weigh themselves daily and call to report small changes in their weights are also able to quickly identify the times when they need extra medicine for their heart. Daily weighing is a less expensive option than an implantable device and it carries no risk of complications. In order to gain approval from insurance companies and popularity with physicians, the makers of the implantable monitor will need to justify their costs.

Expanded Combination of Antibiotics Now Recommended for Ulcer Treatment. Antibiotic experts are fine-tuning treatments for bacteria that cause stomach and intestinal ulcers. About 25 years ago, doctors learned that most of these ulcers were caused by bacteria named Helicobacter pylori (H. pylori). If the bacteria are not treated, an ulcer that has healed will come back within a year. These bacteria are able to withstand stomach acid. To clear the stomach of the bacteria, doctors have had to prescribe a combination of several different antibiotics and anti-acid medicines. However, some strains of the hardy bacteria have become resistant to the antibiotic combination that is usually used. As a result, the infection has persisted in up to 45% of cases even after treatment. A new study published online February 21 by Lancet tested a newer, expanded mix of medicines. The study recommends using four drugs — omeprazole, bismuth, metronidazole and tetracycline — for 10 days to clear the H. pylori bacteria. The drug combination got rid of the bacteria in 4 out of 5 people in the study.

New Clot-Prevention Drug Approved for Atrial Fibrillation. The American College of Cardiology, the American Heart Association and the Heart Rhythm Society have updated guideline for treatment of atrial fibrillation, a heart rhythm disturbance. Patients now have the option to use a new clot-prevention drug called dabigatran (Pradaxa). Warfarin (Coumadin) and dabigatran are both strong clot prevention drugs; aspirin is a more mild prevention treatment. Clot prevention drugs (also called anticoagulants or blood thinners) help prevent strokes, which are a complication of atrial fibrillation. Dabigatran, unlike warfarin, does not require frequent blood tests for monitoring. However, although laboratory costs are saved, the drug is very expensive (about $10 per day). Some experts are worried that overdose or bleeding complications with dabigatran may also be more difficult to treat, because the effects of the medicine 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. Three journals published the updated guideline on February 14: Circulation: Journal of the American Heart Association, Journal of the American College of Cardiology and HeartRhythm Journal.

Americans Should Eat Less Salt. Soon after New Year's resolutions were made, the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services issued new dietary guidelines on January 31. The guidelines sharply cut the limits forsalt in our diets. You can find the guidelines on the USDA website. People older than age 50, black, and anyone with high blood pressure, diabetes or kidney disease are advised to limit sodium to 1,500 milligrams (mg) — roughly a half-teaspoon of salt. For others, the guidelines are more liberal: a daily maximum of 2,300 mg. Although the guidelines singled out people at high risk, that might not be what is best. Many doctors, including experts from the American Heart Association, feel that the stricter 1,500 mg limit is appropriate for all Americans regardless of their age, health or race. Too much salt increases the risk for high blood pressure, heart disease, stroke and death.

Researchers Focus on Protein That Changes Heart Healing. Researchers in a mouse lab have identified a protein that plays an important role in the way a heart heals from a heart attack. This protein, fibronectin-EDA, appears to interfere with proper healing of the heart muscle by promoting a pattern called "remodeling." When mice do not have this protein, they have better heart function after healing from a heart attack. The researchers published their findings in Circulation Research: Journal of the American Heart Association on February 24. They are hopeful—as are readers—that this research might someday lead to better treatment for heart attack patients if scientists can find a way to block this protein.

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.