November 2002

• Blood pressure screening
• Mammograms: To screen or not to screen?
• Treating Carpal Tunnel Syndrome: Surgery or Splinting?
• Food labels to list trans fat

Blood pressure screening

High blood pressure may be the most common chronic condition plaguing adults. Physicians need to know the best method for screening patients to identify and treat those patients with hypertension.

According to previous studies, ambulatory monitoring of blood pressure is the most accurate method. The patient wears a portable device programmed to automatically measure and record blood pressure at frequent intervals. But the device is expensive.

So what is the best alternative? A study published in the August 3, 2002, issue of the British Medical Journal attempts to answer this question. In addition to ambulatory monitoring, blood pressure may be measured by a nurse or doctor, or by the patient. Measurements by a doctor are known to be elevated in some patients because of “white coat hypertension.” In these cases, the anxiety of having one’s blood pressure measured by a doctor causes elevated levels.

One of the purposes of the BMJ study was to determine whether white coat hypertension is seen only in research settings or whether it also turns up in primary care practices. In addition, the study aimed to compare the results of different methods for screening blood pressure. The study involved 200 participants being considered for high blood pressure treatment or who had poorly controlled high blood pressure. Participants had their blood pressure measured multiple times on separate occasions by a doctor, by a nurse, through ambulatory monitoring, and by themselves at home. In general, blood pressure measurements by a doctor were much higher and less accurate compared with the other methods.

The same researchers authored another study in the same issue of the British Medical Journal. They used a questionnaire to determine which method of blood pressure monitoring is most preferred or acceptable to patients. The findings showed patients preferred taking their own blood pressure at home to all the other options. Ambulatory monitoring was less acceptable because it causes discomfort and disturbances to daily life and sleep.

The results of these two studies suggest the most accurate blood pressure readings result from self-screening. If it is not possible, measurement by the patient or a nurse in the clinic will also provide acceptable readings. By screening patients with these methods, patients with white coat hypertension will not be diagnosed with and treated for high blood pressure.

November 2002 Update

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Mammograms: To screen or not to screen?

The mammography debate rages on, newly fueled by results from a Canadian trial published in the Sept. 3, 2002, Annals of Internal Medicine.

The Canadian National Breast Screening Study (CNBSS) is the first trial designed specifically to assess screening mammography in women ages 40–49. In the early 1980s, the CNBSS recruited 50,430 women in this age group with no history of breast cancer. Half were assigned to receive annual mammograms; the other half, to receive “usual care,” meaning that mammograms were done only if a patient’s doctor recommended them.

After an average of 13 years, there were 105 breast cancer deaths in the mammography group and 108 in the usual care group — not statistically significant difference. The researchers concluded that mammograms are not justified for breast cancer screening in women under age 50.

Critics of the CNBSS trial said the data came from older technology, before improved imaging was available. The women who took part enrolled 20 years ago, when mammography images were less clear and radiologists weren’t as proficient at reading them.

But the American Cancer Society, the Centers for Disease Control and Prevention, and the National Cancer Institute advise women to get annual mammograms starting at age 40.

To further muddy the waters, the same issue of Annals of Internal Medicine that carried the CNBSS results published new guidelines for breast cancer screening from the U.S. Preventive Services Task Force (USPSTF). The USPSTF is a panel of health experts that analyzes published research and makes suggestions about preventive health care.

The group recommends having a mammogram every one to two years, starting at age 40. The authors assert that there is no convincing evidence to support the theory that starting annual screening at age 40 exposes women to undue harm, with minimal chances of finding cancer.

On the other hand, if mammograms can find breast cancer, why not start at age 40? For one, the screening test may adversely affect some women. False-positive results (which flag a problem when none exists) can lead to anxiety and further testing.

In defense of its recommendations, however, the USPSTF says that anxiety usually disintegrates after cancer is ruled out. And even when it doesn’t go away, anxiety doesn’t seem to discourage women from continuing their screening regimen.

If you have a family history of breast cancer or other risk factors, it makes sense to start mammograms at age 40 (perhaps earlier, depending upon your level of risk). For everyone else, a discussion with your doctor is the most sensible first step. If she or he feels annual mammograms are unnecessary for you, and you’re comfortable with the decision, waiting until you’re 50 should be fine.

November 2002 Update

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Treating Carpal Tunnel Syndrome: Surgery or Splinting?

When it comes to treating carpal tunnel syndrome, saving the most invasive for last may not be such a good idea. A study in the September 11, 2002, issue of the Journal of the American Medical Association (JAMA) suggests surgery, usually the last resort, may work better than splinting for some people suffering from the condition.

Carpal tunnel syndrome causes aching, tingling, or numbness in the hand when the median nerve running through the wrist is compressed or damaged. Splinting the wrist and hand at night is the most common treatment. Other conservative treatment options include anti-inflammatory drugs or corticosteroid injections into the wrist to relieve inflammation. If all else fails, surgery can cut a ligament in the wrist and relieve pressure on the nerve.

In the JAMA study, Dutch researchers compared splinting to surgery. A total of 176 patients either wore a splint at night for six weeks or received surgery on the wrist. In the following 18 months, participants completed questionnaires on how they felt. Physical therapists also assessed their progress.

After three months, 80% of the surgery patients had improved, compared to only 54% of the patients who wore a splint. Patients in the surgery group were also more likely to experience complete recovery than patients in the splinting group. Even after 18 months, surgery was still more successful at relieving the symptoms. In fact, by the end of the study, 41% of the patients in the splinting group had gone on to receive surgery.

These results suggest surgery may be the best first-line treatment option for some people with carpal tunnel syndrome. However, it may not be the ideal treatment for everyone; the study did not include pregnant women or people with diabetes. Further research is needed to determine how surgery measures up against anti-inflammatory drugs or corticosteroid injections.

November 2002 Update

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Food labels to list trans fat

Sometime next year the Food and Drug Administration will require food makers to list how much artery-damaging trans fat their products contain.

Trans fats, also called trans fatty acids, are found in hydrogenated or partially hydrogenated vegetable oils. Trans fatty acids are the byproduct of partial hydrogenation, a process that solidifies unsaturated oils. Hydrogenation increases the shelf life of products made with these oils, yet it also turns the relatively “safe” unsaturated fats into trans fatty acids, which are no better (and possibly worse) than saturated fat. Saturated fat had long been heralded as the “bad” kind of fat until research in the 1990s showed that trans fat is actually worse.
In a report to the FDA earlier this year, the Institute of Medicine said Americans should cut back their intake of trans fats but there was not enough research to recommend a safe daily level.

According to federal officials, trans fat will be labeled on a separate line from saturated fat, telling people exactly how much of each they are eating. Until food labels are changed, however, the only way to know what you're eating is to read food labels carefully. If partially hydrogenated oil is listed as one the first ingredients, the product likely has a lot of trans fat. Deep fried foods, such as donuts and French fries, top the list of food with high levels of trans fats.

There are also many “hidden” sources of trans fats, including vegetable shortening and stick margarines. The rule of thumb with margarines and spreads is the softer, the better (that is the lower in trans fats). Trans fats also occur naturally in meat, but at much lower levels.

November 2002 Update

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