Ignorance is bliss? Or is it? And if so, when? Some people adopt an attitude that what they don’t know can’t hurt them. Alas, the ostrich attitude is not helpful, especially when HIV testing, blood pressure, cholesterol levels and breast or colon cancers are concerned. Yet the situation is far from being simple. Some screenings, especially in the right target group, bring positive benefits to the patients. Other screenings, however, can engage the patient in a host of expensive, dangerous and useless medical procedures that cause more harm than good.
Most people are well aware of commercial screening companies that come to a local church or a medical provider-sponsored health fair. But are the tests really indicated and what are their benefits? Fortunately, the United States Preventative Services Task Force (USPSTF), an independent organization of highly qualified professionals, examine the science behind the testing to help answer those questions.
Commercial screening companies often propose the following tests: (1) Ultrasound screening of the carotid arteries, (2) EKG for “coronary heart disease” or “atrial fibrillation,” (3) Ultrasound for abdominal aortic aneurysm, (4) Ankle-brachial index for peripheral arterial disease and (5) Heel bone densitometry for osteoporosis. Let’s look at the evidence from the USPSTF.
“Stroke/Carotid Artery Screening” sounds like a good idea, but the USPSTF gives it a “D” grade (“Don’t do it!”) in asymptomatic adults. Why? The test should be reserved for those who have had symptoms or signs suggestive of arterial blockage (i.e. mini-strokes, dizziness, transient ischemic attacks, a “bruit” identified on physical exam, etc.) Screening patients without symptoms can result in many false positives (no real disease) and referrals for subsequent procedures, like angiography or even surgery, which may offer no benefit and entail cost and documented risks.
EKG’s (electrocardiograms) are simply and effective in the right group, those with an irregular heartbeat (or cardiac symptoms). Rhythm irregularities can be identified by the primary care doctor (or nurse or physician’s assistant) when taking the pulse. In the general population, “abnormal EKG’s” can be common and may or may not have any clinical significance. Subsequent testing (treadmills, heart ultrasounds, calcium scoring, or even heart catheterization) can all produce false positive examines, and each has its own expense and potential for problems. The USPSTF gives screening EKG’s a “D” grade for diagnosing coronary heart disease in the general population.
While abdominal aortic aneurysms can be life-threatening, they can be small and medically insignificant. The USPSTF only recommends “Abdominal Aortic Aneurysm Screening” tests in male smokers between 65 and 75 years of age (“B” Grade). It gets a “C” (neither recommended not discouraged) for non-smoking males between 65-75 years old and is not recommended (“D”) for asymptomatic women.
This leads us to “Peripheral Arterial Disease Screening” with an ankle-brachial index. The test is simple, with a comparison of systolic blood pressures between the arm and ankle. A low index may indicate peripheral artery disease, presumably from blockage somewhere in the lower extremity. About 6% of adults over 40 can have a low index (<0.9), with higher percentages among diabetes and those with cardiovascular disease. The USPSTF gives this an “I” (insufficient evidence for recommendation.) Anyone with claudication (leg pain with walking) should certainly be tested, especially if they are diabetic or have known heart disease.
Finally, there is “Osteoporosis Risk Assessment”. Osteoporosis is thinning of the bones and it can affect some post-menopausal women, increasing their risk for broken bones, notably hip and vertebral fractures. The USPSTF gives this screening a “B” for women over 65 and younger women with known risk factors (i.e. smoker, early menopause, hysterectomy, etc.). It receives an “I” (insufficient evidence for recommendation) for men.
This is not an exhaustive review, but just an evaluation of some frequently performed commercial screening tests. It is best to look up any screening test on the USPSTF website at http://www.uspreventiveservicestaskforce.org/recommendations.htm, where science, not monetary self-interest, dictates the decision making. In short, screenings can be good, but not necessarily every test for every individual every time.