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Medical Checkups and Screening Tests

Return to Chapter Index

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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Annual PSA Test May Not be Necessary for All Older Men

Prostate cancer is the second leading cause of death for men in the United States. And while the chance of being diagnosed with prostate cancer over a lifetime may be as high as 20%, the chance of dying of prostate cancer is only about 3%. But the risk of prostate cancer increases with age. More than 75% of all cases occur in men over 65, and about 40% of men over 80 have the disease. When it is diagnosed early, prostate cancer is more likely to be treated successfully. Cure rates are excellent for cancer that is discovered and treated when it is still confined to the prostate gland. About 95% of men with localized prostate cancer treated by surgery are alive after five years.

The prostate-specific antigen (PSA) test is a primary test for finding early-stage prostate cancer. PSA is a protein produced by the prostate gland, and PSA levels become elevated in men with prostate cancer. Although some respected groups recommend an annual PSA test for all men over age 50, the annual PSA test remains controversial. That is, in part, because it has a high chance of being falsely negative (20%-40% of men with prostate cancer have normal levels of PSA) or falsely positive (PSA levels may be elevated in men with noncancerous prostate conditions).

At a meeting of the American Society of Clinical Oncology, researchers presented findings that indicated that an annual PSA test may not be warranted in men over 50 with an initial normal PSA (0–4 nanograms/milliliter). For five years, researchers tracked the annual PSA test results of 27,863 men ages 55–74 whose PSA levels were initially normal. . They found that 98.6% of men with a PSA result of less than 1 ng/ml at baseline would remain negative after 4 more annual tests and that 98.8% of men with a baseline PSA of 1–2 ng/ml would have a negative PSA test the following year.

Based on these results, the researchers concluded that performing a PSA test every five years on men with an initial PSA less than 1 ng/ml and every two years for men with a PSA of 1–2 ng/ml would reduce the number of PSA tests performed by 55%. This would save money and help men avoid the anxiety associated with yearly prostate tests.

July 2002 Update

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New Guidelines for Managing Women with Abnormal Pap Smears

Each year 3.5 million women have some degree of abnormality on their Pap smear — the test most commonly used to screen for cervical cancer — and require additional attention. But until 2001 there were no national guidelines on the best way for clinicians to treat these women.

The American Society of Colposcopy and Cervical Pathology brought together experts in cervical cancer prevention to develop comprehensive specifications. The guidelines they created could make things easier for women who have inconclusive Pap smear results.

The most common abnormal Pap smear result, occurring in about 1 in 20 tests, is called atypical squamous cells of undetermined significance (ASC-US). While most women with ASC-US do not have a significant cervical lesion and only about 1 in 1,000 have cervical cancer, they are at considerable risk for a high-grade cervical cancer precursor lesion and require some form of follow-up.

The conference evaluated data supporting different approaches of ASC-US management and found that three are safe and effective: repeating the Pap test at least twice over an 8-12 month period, inspecting the cervix with a colposcope and obtaining cervical biopsies, and testing for human papillomavirus (HPV), a sexually transmitted disease that causes genital warts and is linked to most cases of cervical cancer.

According to the Consensus Conference judgment, women with abnormal Pap tests that are not ASC-US need to undergo a colposcopic examination (inspection of the cervix using a microscopy) and cervical biopsies.

The guidelines also tout a relatively new technique, liquid-based cervical cytology, in which cervical cells are collected in liquid instead of smeared onto a slide, as in a Pap smear. The liquid-based screening makes more cells available if additional HPV testing is needed, which means women would only need to have one sample taken.

The complete set of guidelines can be found in the April 24, 2002, issue of the Journal of the American Medical Association.

June 2002 Update

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High-Normal Blood Pressure Bad for the Heart

People with high-normal blood pressure are more likely to suffer a heart attack, stroke, or heart failure than those with lower blood pressure, according to recent findings from the Framingham Heart Study.

The researchers followed the cardiovascular events of 6,859 participants of the famed study, which has been monitoring subjects from the Boston suburb for more than 50 years. A third of participants had normal blood pressure (120–129 over 80-84 mm HG), a quarter had high-normal (130–139 over 85–89 mm Hg), and the remainder had optimal blood pressure (less than 120 over less than 80 mm HG). People with high blood pressure were excluded from the study.

Of those in the optimal category, 81 had cardiac events, over a ten-year time period, compared to 136 people in the normal blood pressure category and 180 in high-normal category. In all, people with high-normal blood pressure were two to three times more likely to suffer a heart attack, stroke, or heart failure than those with lower blood pressure. This held true in both men and women, and was consistent in both age groups (35 to 64 and 65 and over), even after researchers adjusted for other cardiovascular risk factors such as smoking and obesity. Indeed, the study found risk increases in a stepwise fashion as blood pressure increases.

Blood pressure reflects how hard your heart is working and what conditions your arteries are in. Risk factors include heavy drinking, smoking, eating a diet high in salt, obesity, and family history. Doctors generally get alarmed only if systolic blood pressure is above 140 mm Hg or if diastolic blood pressure is above 90 mm Hg. However, this study calls for further research to be done to see if patients in the high-normal group benefit from lowering their blood pressure.
December 2001 Update

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FDA Approves First Automatic and Non-Invasive Blood Glucose Monitor

People with diabetes who regularly monitor their blood glucose levels are less likely to develop the disease’s complications such as heart disease, blindness and kidney disease. Unfortunately, traditional blood glucose monitoring is time-consuming and requires sticking the finger for blood. So many diabetics test themselves less frequently than recommended.

A new bloodless glucose-monitoring device recently approved by the FDA could make monitoring easier. Made by Cygnus Inc., GlucoWatch Biographer is a prescription wristwatch-like device with sensors on its underside that monitor glucose levels. By a process called reverse iontophoresis, it applies a very low electric current to extract glucose samples from the skin’s interstitial fluid every 20 min for 12 hours, even during sleep. The device, which must be first calibrated using a finger-prick reading, stores the readings and sounds an alarm if the glucose reaches a pre-selected level.

The FDA approved the device on the basis of clinical trials done on both type I and type II adult diabetics. No research has been conducted on children. The studies compared GlucoWatch readings with traditional finger-prick blood glucose tests and found measurements were fairly consistent. However, up to 25% of the time, the results differed by more than 30% and sometimes GlucoWatch gave completely erroneous readings. The device was less effective at detecting very low glucose levels than very high levels. Also, it was not accurate if the patient’s arm was too sweaty and perspiration is common with hypoglycemia, or low blood sugar. GlucoWatch caused skin irritation in up to 50% of users.

GlucoWatch should not be used as a replacement for finger-prick blood tests. Any treatment decisions and all alarm values should be confirmed with blood glucose tests. But as the first automatic and non-invasive device, GlucoWatch may help patients better manage their diabetes.
June 2001 Update

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National Cholesterol Education Program Releases New Guidelines for Treating and Preventing High Cholesterol

On May 15, 2001, the National Cholesterol Education Program (NCEP) — coordinated by the National Heart, Lung, and Blood Institute (NHLBI) — released the first major revision of its recommendations for detecting and lowering high cholesterol in adults since 1993.

One of the fundamental features of the new guidelines is the accurate assessment of heart disease risk using a new "global risk assessment tool" that combines multiple risk factors into a measure of a person's absolute risk of developing coronary heart disease within the next 10 years. According to the guidelines, patients who have a risk of 20% or higher should receive aggressive therapy to control cholesterol levels. In addition to aggressive treatment of high LDL cholesterol, as laid out in the 1993 report, the revised guidelines also recommend a more assertive treatment approach for diabetes, low HDL levels, and high triglyceride levels.

Specific changes include:

  • Treating high cholesterol more aggressively for those with diabetes, even if they do not have heart disease.
  • A full lipid profile (which measures total cholesterol, LDL, HDL, and triglycerides) as the first test for high cholesterol (rather than simply testing total cholesterol and HDL and performing a full lipid profile only if total cholesterol is high).
  • A new level at which low HDL becomes a major risk factor for heart disease. The 1993 guidelines defined a low HDL as less than 35 mg/dL; now it is less than 40 mg/dL.
  • More aggressive treatment of high triglyceride levels.
  • Advising against the hormone replacement therapy (HRT) as an alternative to cholesterol-lowering drugs for post-menopausal women.

Another key change in the guidelines is intensified lifestyle recommendations regarding nutrition, exercise, and weight control to treat high cholesterol. The updated diet advises that less than 7% of daily calories come from saturated fat and limits dietary cholesterol to less than 200 mg per day. It also allows up to 35% of daily calories from total fat, provided most come from unsaturated or monounsaturated fat, which doesn't raise cholesterol levels. Additionally, the guidelines strongly underscore the need for weight control and physical activity, both of which improve various heart disease risk factors.

The revised recommendations also emphasize careful attention to the metabolic syndrome, a particular cluster of cardiovascular risk factors that is becoming increasingly common in the United States. Characteristics of metabolic syndrome include too much abdominal fat, high blood pressure, high blood sugar, elevated triglycerides, and low HDL.

For more information, see the "Live Healthier, Live Longer" Web site by going to the NHLBI home page at www.nhlbi.nih.gov and clicking on ATP III Cholesterol Guidelines under Highlights.

2001 Cholesterol Guidelines
Total Cholesterol Level Total Cholesterol Category
Less than 200 mg/dL Desirable
200-239 mg/dL Borderline High
240 mg/dL and above High
LDL Cholesterol Level LDL Cholesterol Category
Less than 100 mg/dL
Optimal
100-129 mg/dL Near optimal/above optimal
130-159 mg/dL Borderline high
160-189 mg/dL High
190 mg/dL and above Very high
Trigylceride Level
Triglyceride Category
Less than 150 mg/dL Normal
150-199 mg/dL Borderline high
200-499 High
Greater than or equal to 500 Very high
HDL Cholesterol Level HDL Cholesterol Category
Less than 40 mg/dL Low (representing increased risk)
60 mg/dL and above High (heart protective)

 

Three Categories of Risk that Modify
LDL Cholesterol Goals
Risk Category LDL Goal (mg/dL)
Coronary Heart Disease (CHD) and CHD equivalents Less than 100
Multiple (2+) risk factors Less than 130
0-1 risk factor Less than 160
Risk factors (exclusive of LDL cholesterol): cigarette smoking; blood pressure greater than or equal to 140/90 mm Hg or on antihypertensive medication; HDL cholesterol less than 40 mg/dL; a family history of coronary heart disease before age 55 in a father or brother or age 65 in a mother or sister; age above 45 for men and 55 for women

May 2001 Update

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A New Approach to Testing for Cervical Cancer

Most women know that regular Pap smears can almost eliminate the chances of developing invasive cervical cancer. By examining the cervix for abnormal (and potentially precancerous) cells, treatment can be started before a real problem develops.

What many women may not know is that human papilloma viruses (HPVs) (which cause genital warts) are responsible for the majority of cases of cervical cancer. Two recent studies suggest that regular screening for HPV may prove even more effective than the traditional Pap smear in preventing cervical cancer.

The first study included 8,554 women who lived in the Gaunacaste Province of Costa Rica, where there is a very high rate of cervical cancer. Researchers found that HPV testing picked up 17% more high-grade cervical cell abormalities and cancers.

The second study compared the Pap smear with testing vaginal samples for HPV. 1,415 women in South Africa (who had not had any cervical cancer screening) participated. The first HPV test was done by a doctor during a routine physical exam. The HPV test was done on samples of vaginal fluid the women collected themselves using a cotton swab. All the women had Pap smears done as well. The HPV testing on samples taken by the doctor detected far more cervical disease than the Pap smear (84% vs. 68%). The HPV testing done on the self-collected samples was not equivalent to the HPV tests done on the physician-collected samples, but was just as good as the Pap smear. And did not require a trip to the doctor’s office.

What are the important take-home messages from these studies? First, each year in the United States there are an estimated 15,000 new cases of cervical cancer. Each year, about 5,000 women will die needlessly of the disease. Regular Pap smears are the most effective way to screen for this disease. Second, although HPV is one of the most common sexually transmitted infections, only a small number of women suffer complications, including cervical disease. There are over 70 types of HPV, but only 13 are known to cause cervical cancer.

Still, screening techniques that include HPV testing may not only increase the ability to detect abnormal cell changes early, but can also let a woman know whether or not she carries one of the more dangerous viruses (and therefore needs to be extra vigilant about screening). Finally, self-collected samples for testing may take us a big step forward in preventing this disease in places where women do not get regular visits to the doctor.

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Screening Children for Type 2 Diabetes

As obesity in the United States reaches epidemic proportions, the number of children diagnosed with type 2 diabetes has been increasing dramatically. Until recently, type 1, or juvenile-onset, diabetes was the most common form of the disease in this age group, so many children with type 2 diabetes have been either undiagnosed or misdiagnosed as having type 1 diabetes. Research suggests that a child age 10 (or younger if puberty begins before age 10) should be screened every two years for type 2 diabetes if he or she is 120% or more of his or her ideal weight and has one or more of the following risk factors:

  • a family history of type 2 diabetes in first- or second-degree relatives (that is, in a sibling, parent, grandparent, cousin, blood aunt or uncle)
  • is American Indian, African-American, Hispanic, Asian, South Pacific Islander
  • has signs of insulin resistance (for example, excess sugar in the urine) or conditions associated with insulin resistance (for example, dark, velvety patches on the skin or high blood pressure)

Because a decrease in physical activity and an increase in the intake of calories and fat are major causes of obesity, personal preventive measure can be taken against the onset of type 2 diabetes in children. When a child's blood glucose levels are still normal, or even if they are elevated but not enough for a diagnosis of diabetes to be made, taking action can have long-term benefits in all children at high risk for type 2 diabetes. Overweight or obese children with any of the bulleted risk factors mentioned above should be strongly encouraged to maintain a healthy diet (high in fruits and vegetables and low in fat) and to exercise at least 30 minutes per day.
October 2000 Update

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