Update From the Medical Journals: January 2010
January 29, 2010
By Mary Pickett, M.D.
What's the latest news in the medical journals this month? Find out what your doctor is reading.
The New England Journal of Medicine released a report online on January 20 making it clear that Americans can improve their health and reduce health-care costs if they are willing to eat a less salty diet. The report comes from epidemiologists at Johns Hopkins University.
The researchers used a computer simulation to predict the health benefits nationwide, if adults 35 years and older reduced average salt intake by 3 grams per day. (This equals 1,200 milligrams of sodium per day). The computer simulator used predictable relationships between salt and blood pressure, and between blood pressure and heart or stroke events. According to predictions, during the first decade after Americans cut back, there would be from 54,000 to 99,000 fewer heart attacks per year, 32,000 to 66,000 fewer strokes per year, and 44,000 to 92,000 fewer deaths per year from any cause. Roughly one-fourth of all people who currently need medication to treat high blood pressure would be able to stop taking their medications.
Most Americans eat a total of about two teaspoons of salt in a day men take in 10.4 grams of salt per day on average, and women consume 7.3 grams per day. Cutting salt by 3 grams is an ambitious change. But even if we reduce salt intake by an average of 1 gram per day even if it's over the next decade we would save somewhere between $19 billion and $32 billion in health care costs over the next ten years. If we cut out 3 grams of salt per day on average, Americans as a nation could save between $57 billion and $97 billion health care dollars over the next ten years.
Most of the salt we eat 75% to 80% comes from processed foods. With our health and health dollars at stake, some experts are making a case that it may be appropriate for the U.S. Food and Drug Administration to regulate the amount of salt that can be allowed in processed food products.
A study in the January 27 issue of JAMA compared two different ways to prevent episodes of atrial fibrillation, a common irregular heart rhythm. The study evaluated people in whom the irregular rhythm only occurs intermittently (also called paroxysmal) and who did not respond to treatment with a rhythm-control drug. The study suggests that a procedure called ablation causes better rhythm control and slightly fewer serious complications than treatment with additional drugs that are meant to prevent the arrhythmia.
An ablation procedure for atrial fibrillation involves placing a catheter in an artery and threading the catheter into the heart. Instruments at the tip of the catheter are used to map out the flow of electricity in the heart and to cauterize (burn) a small area of heart muscle where the pulmonary veins empty into the heart. For most patients who have intermittent atrial fibrillation, this treatment appears to eliminate the trigger for the rhythm change.
In the study, 167 patients were randomized to receive either ablation or additional drug treatment. About two-thirds of the patients got the ablation procedure. Sixty-six percent of them stayed symptom-free during the subsequent nine months. Only 19% of people in the drug-treatment group had the same success. About 5% of individuals treated with ablation had serious complications, which compared well to the drug-treatment group. Complications of ablation can include other rhythm problems, such as atrial flutter, inflammation of the sac that surrounds the heart (pericarditis) and slow emptying of the stomach caused by damage to nerves that are near the heart.
This study is helpful because it gives us information about a procedure that is new, but becoming more popular. For the time being, this procedure is not for people whose usual or "chronic" rhythm is atrial fibrillation. In addition, except for people who have bothersome symptoms, preventing episodes of the arrhythmia (known as rhythm control) may be a less safe or helpful strategy than simply controlling the heart rate during episodes when they occur (rate control). The blood-thinning medicine warfarin (Coumadin) is recommended for most people with atrial fibrillation as a way to prevent strokes. (Strokes are a complication of atrial fibrillation.) This is true whether or not the rhythm problem has been treated with ablation.
Longer follow-up from this study will eventually give us a better idea about the value of ablation for treating intermittent (paroxysmal) atrial fibrillation. If its benefits last long-term, this procedure may become more widely recommended.
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.