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2 March 2010 Annals of Internal Medicine Tip Sheet

Annals of Internal Medicine is published by the American College of Physicians on the first and third Tuesday of every month. These highlights are not intended to substitute for articles as sources of information. For a copy of an article, call 1-800-523-1546, ext. 2656, or 215-351-2656, or visit www.annals.org. Past highlights are accessible as well.

1. Early Release: Decreasing U.S. Population Sodium Intake Could Prevent Heart Attacks, Extend Lives, and Save Billions of Dollars in Health Care Costs: Collaboration with Food Industry May Help

Americans consume 3,900 mg of sodium per day, 75 percent of which comes from processed food. Health care experts recommend that healthy adults consume no more than 2,300 mg of sodium per day, as too much sodium can increase blood pressure, putting patients at risk for heart attack and stroke. Since moderate reductions in sodium intake can reduce systolic blood pressure, several countries, including the U.S., are considering strategies to reduce population sodium consumption. Researchers sought to determine the cost-effectiveness of two approaches to the problem government collaboration with food manufacturers to voluntarily reduce sodium in processed foods, or a sodium tax. They constructed a computer model to determine how these strategies could influence population level heart attack and stroke. The researchers found that collaboration with industry would be the better approach, as it would decrease mean population sodium intake by 9.5 percent, and prevent 513,885 strokes and 480,358 heart attacks over the lifetime of adults age 40-85 alive today compared to the status quo. This would increase quality-adjusted life-years by 2.1 million and save $32 billion in health care costs. A tax on sodium would decrease population sodium intake by 6 percent and increases quality-adjusted life-years by 1.3 million and saves $22.4 billion over the same time period. Thomas Frieden, head of the CDC, provides editorial comment.

2. Adding ECG to Health Exam May Prevent Sudden Cardiac Death in Young Athletes

Each year, two in 100,000 young athletes succumb to sudden cardiac death. While the mandate to screen young athletes prior to participation in sports is universal, the practice guidelines that define screening recommendations are not uniform. The European Society of Cardiology and the International Olympic committee recommend that pre-sports screening include electrocardiography (ECG), but other medical organizations recommend limiting screening to a focused medical history and physical examination. Researchers studied 510 college athletes to determine if the addition of routine ECG to history and physical examination improved the detection of cardiac abnormalities. They found that adding ECG to the health exam increased detection from five to 10 out of 11 but increased the false positive result rate from 5.5 percent to 16.9 percent. These results suggest that preparticipation screening limited to medical history and physical examination fails to identify a significant percentage of athletes with increased risk for adverse cardiac events, but adding ECG results in more false alarms.

3. ECG Screening May be a Cost-effective Strategy to Prevent Sudden Cardiac Death in Young Athletes

Occult cardiovascular disease is the leading cause of sudden death in young athletes. However, an ongoing debate exists surrounding the optimal approach to screening young competitive athletes for heart abnormalities. Some medical organizations recommend that pre-sports screening include electrocardiography (ECG), while others recommend limiting screening to a focused medical history and physical examination. Including 12-lead ECG in the preparticipation screening of young athletes is controversial because of concerns about cost-effectiveness. Researchers reviewed data for high school and college competitive athletes aged 14 - 22. They found that adding ECG to the current recommended screening strategy of medical history and physical examination reduces sudden death with a cost ratio of $42,900 per life-year. Screening athletes with a cardiovascular-focused history and physical alone is unlikely to save money when compared with a strategy of no screening. The researchers conclude that despite concerns about total cost, the incremental life-years saved by including ECG in student-athlete exams are significant.

4. Vitamin D Supplementation May Reduce Risk for Heart Disease

Many elderly Americans have an inadequate intake of vitamin D and calcium. Beyond their pivotal role in bone health, vitamin D and calcium have received increasing attention for their cardiovascular benefits, among other advantages. Researchers sought to determine whether vitamin D and calcium supplements reduce the risk for cardiovascular events in adults. They reviewed 17 prospective studies and randomized trials that examined the effect of vitamin D supplementation, calcium supplementation, or both on the risk for cardiovascular events in adults. The researchers found that vitamin D supplements at moderate-to-high doses may possibly reduce cardiovascular disease risk. However, calcium supplements appear to have little or no cardiovascular benefits.

5. Clinical Observation: In the Long Term, No Difference Between Low-Fat and Low-Carbohydrate Diets for Obese Patients

Results of a randomized, controlled trial found greater weight loss at six months with a low-carbohydrate diet than with a calorie restricted, low-fat diet in 132 patients with a mean weight of 288 lbs and a high risk of diabetes. However, after 12 months, there were no significant differences in weight loss. Findings at three years were similar, but the pattern of weight change from 12 to 36 months differed. While the low-carbohydrate group lost more weight at 12 months, they regained more weight during the next 24 months. In contrast, the low-fat group maintained their weight loss. The difference in weight regain may reflect initial weight loss, as greater weight loss from baseline to 12 months was associated with greater weight gain.