Update From the Medical Journals: April 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.

American Heart Association Says Triglycerides Should Be Less than 100
Troponin Blood Tests After Surgery Reveal Silent Heart Attacks
One Third of Resistant Hypertension is Actually "White Coat" Hypertenstion
More News in Brief: Drug Combination May Promote Weight Loss; Vaginal Gel Lowers Risk for Premature Birth

Your triglyceride level — the blood fat that is measured along with cholesterol — doesn't get as much attention as the LDL and HDL cholesterols. But a high triglyceride level can contribute to your heart disease risk. The American Heart Association (AHA) has revised its recommendation for how low this number needs to be for ideal heart health. The new guideline says people should aim for a level below 100mg/dL. The recommendation, along with a review of research, was published April 18 in the journal Circulation.

About one third of Americans have triglyceride levels that are above 150 milligrams per deciliter (mg/dL). The new guideline does not recommend medicines to help you lower your triglycerides except in severe cases. Instead, it advises lifestyle changes. We know from past research that diet and exercise can lower triglycerides by 50% or more.

Limit foods with added sugar (sweeteners that are added during processing or cooking) to about 100 calories per day for women and 150 calories per day for men. The fastest way for most Americans to reduce added sugar is to cut down on sodas and other sweetened drinks.

Limit fructose to less than 100 grams per day. To cut back, drink less fruit juice. Juice is naturally sweetened by fructose. For fresh fruits, choose tart or bland fruits that are lower in fructose. Good choices are cantaloupe, grapefruit, strawberries, peaches and bananas.

Reduce saturated fats in your diet.

Avoid trans fats. These fats are found in hydrogenated and partially-hydrogenated oils, which are ingredients in processed foods.

Include healthier unsaturated fats and omega-3 fatty acids in your diet by eating fatty fish like salmon, trout and tuna.

Reduce or avoid alcohol.

Eat more vegetables and high fiber whole-grain foods.

Exercise for 150 minutes or more each week.

Heart attacks are common during and after any type of surgery. Post-surgery heart attacks are more common because the body shifts its balance of blood clotting proteins in order to heal wounds. The body's reaction to stress and anesthesia may contribute to the risk for heart attack, too. Some patients have a "silent" heart attack where they don't notice any symptoms.

Researchers studied the records for 8,351 patients in 23 countries to see how often heart attacks occur after surgery and if there are ways to identify which patients are at risk. The Annals of Internal Medicine published the results April 19.

Five percent of patients who had surgery had a heart attack as a complication of surgery; 74% of the heart attacks occurred in the first 48 hours after surgery. Sixty-five percent of patients had a "silent" heart attack. Silent heart attacks did as much heart muscle damage as heart attacks with symptoms.

The researchers monitored patients for heart attacks after surgery using blood tests. In the first days after surgery, researchers measured a heart protein named troponin. The level of this protein goes up in the first day of a heart attack. Troponin levels are routinely checked when a person is having chest-pain symptoms. However, it is not the standard to check this test in a person who is recovering from surgery if there are no chest-pain symptoms. The researchers suggest that it should be standard practice to check patients' troponin levels one or more times in the first days after surgery. This would allow better treatment for silent heart attacks. It is a worthwhile suggestion.

Some people have high blood pressure readings only when they are in a doctor's office. This is called "white coat" hypertension. It is very common. Most people think being nervous causes white coat hypertension.

Findings from a new study show that more than one third of 8,295 patients being treated for resistant hypertension actually had white coat hypertension. (Resistant hypertension means that a person has high blood pressure readings in the doctor's office despite being on three blood pressure medications.) The study first appeared online March 28. It will be published in the May issue of Hypertension: Journal of the American Heart Association.

Researchers had people check their blood pressure at home every 20 minutes for 24 hours. This is called "ambulatory blood pressure monitoring." Thirty-seven percent had normal readings.

Doctors disagree about whether white coat hypertension should be treated with medicines. Studies don't always show that treatment for white coat hypertension improves health. People with white coat hypertension have a lower risk for heart disease and kidney damage from high blood pressure compared with people who have true resistant hypertension. It may be worthwhile to use ambulatory blood pressure monitoring more often to better advise patients about their heart risk.

Drug Pair May Promote Weight Loss. Drug makers have not yet been able to develop a weight loss pill that is both safe and effective. Researchers are optimistic, however, that two drugs already on the market — phentermine (Apidex) and topiramate (Topamax) — could promote weight loss when taken together. The Lancet published a study online April 10 that looked at the safety of this drug combination. The results were promising. Phentermine is a weight loss pill. It is modestly effective. Unfortunately it's easy to regain weight if you stop taking it. Topiramate is a seizure medicine. In the study, 1,493 patients were given the two drugs. Another 994 patients were given a placebo pill. The study participants were randomly assigned to their groups. They were coached on ways to improve their diet and exercise. After a year, people who had been taking the placebo pill lost 3 pounds. People who had been taking a low dose of the two drugs had lost an average of 18 pounds. People who got a higher dose of the drugs had lost a bit more weight, but they also had many more side effects. The U.S. Food and Drug Administration (FDA) has not approved this drug combination to treat obesity. The study may allow the FDA to give topiramate a new "indication" for weight loss. There are no long-term studies on this combination of drugs for weight loss.

Vaginal Gel Lowers Risk for Premature Birth. Some pregnant women naturally have a short cervix. This can be seen on prenatal ultrasound tests. The cervix is the part of the uterus through which the baby comes out. The cervix needs to stretch and shorten during labor before a baby can be delivered. When a woman has a short cervix to begin with, there is a risk for premature labor and delivery. A vaginal progesterone gel can reduce the risk for preterm birth when a mother has a short cervix, according to a new study. Women using the gel had 45% fewer deliveries before the 33rd week of pregnancy. Babies of women using the progesterone gel also had fewer breathing complications at birth. The progesterone gel was compared to a placebo gel. The study was published online April 6 by the journal Ultrasound in Obstetrics and Gynecology. Treatment with progesterone may become a standard part of prenatal care for women who have a short cervix.

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.