Should you screen—or not? The latest recommendations: while USPSTF recommendations on hypertension and sickle cell disease have stayed the same, those for Chlamydia and carotid artery stenosis have changed

Journal of Family Practice, July, 2008 by Doug Campos-Outcalt

Not enough time and too many potential tests to do. This is the problem faced daily by family physicians. We want to practice up-to-date preventive medicine, but there's little time to analyze the latest studies. Thankfully, we can rely on the United States Preventive Services Task Force, the organization with the most rigorous evidence-based approach, to do the legwork for us. (1)

Last year, and in the early part of this year, the Task Force issued a number of recommendations on topics ranging from hypertension screening to screening for illicit drug use. (See TABLE 1 for a breakdown of the 5 categories of recommendations.)

While some of these recommendations (TABLE 2) were reaffirmations of past recommendations, others included some changes.

The Task Force has:

* dropped the age for routine screening for Chlamydia in sexually active women from 25 years and younger to 24 and younger.

* added a recommendation against the use of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) to prevent colorectal cancer (CRC).

* changed its recommendation on screening for carotid artery stenosis.

In 1996, the Task Force noted that the evidence was insufficient to make a recommendation; in 2007 it recommended against such routine screening.

* added recommendations on counseling patients about drinking and driving, as well as on screening for illicit drug use. In both cases, the Task Force says the evidence is insufficient to recommend for or against.

* Continue to screen for HTN, sickle cell, Chlamydia

The latest A and B recommendations from the Task Force largely reaffirm previous recommendations. These recommendations cover hypertension, sickle cell disease, and Chlamydia.

Hypertension. Screening and treatment of hypertension in adults leads to lower morbidity and mortality from cardiovascular disease and is still recommended. (2)

Sickle cell disease. Screening newborns for sickle cell disease and treating those affected with oral prophylactic penicillin prevents serious bacterial infections. It also remains a recommended service. (3)

Chlamydia. Following a review of the evidence, the Task Force reconfirms the benefits of screening for Chlamydia in sexually active young women, but it has changed the age cutoff. In 2001, the Task Force indicated that sexually active women who were 25 years of age and younger should be screened. In 2007, the Task Force dropped the age to 24 and younger.

The latest recommendation reaffirms the need to screen women (above the cutoff) who are at risk--that is, women who have previously had a sexually transmitted infection (STI), those who have a new or multiple sex partners, and those who exchange sex for money or drugs. (4) Screening is recommended annually; nucleic acid amplification tests are acceptable, allowing testing of urine or vaginal swabs.

Screening during pregnancy is recommended for the same groups--women who are 24 and younger and older women at risk--at the first prenatal visit and again in the third trimester if risk continues. Chlamydia is the most common bacterial STI, and screening and treatment prevents pelvic inflammatory disease in women and leads to improved pregnancy outcomes.

* Interventions that are not recommended

Chemopreventon of colorectal cancer. For the first time, the Task Force issued a recommendation on the use of aspirin or other NSAIDs to prevent CRC. The Task Force does not recommend the routine use of these agents. (5) The dosage needed to prevent CRC is high-er than that which prevents cardiovascular disease and can cause significant harm.

Aspirin use is associated with gastrointestinal bleeding and hemorrhagic stroke; NSAID use is associated with gastrointestinal bleeding and renal impairment. The Task Force concludes that in the general adult population, potential harms exceed potential benefits.

Screening for carotid artery stenosis. In 1996, the Task Force found insufficient evidence to recommend for or against routine screening for carotid artery stenosis. In 2007, the Task Force made a recommendation against routine screening for carotid artery stenosis. (6) Screening with duplex ultrasonography results in frequent false positives. Confirmatory testing with angiography is associated with a 1% rate of stroke. Endarterectomy itself has a death or stroke rate of about 3%.

In the general population, close to 8700 adults would need to be screened to prevent 1 disabling stroke. The Task Force indicates that primary care physicians would have better outcomes by concentrating on optimal management of risk factors for cerebral artery disease.

Screening for bacterial vaginosis among low-risk pregnant women. The final D recommendation pertains to screening for bacterial vaginosis during pregnancy to prevent preterm delivery. (7) Pregnant women who have not had a previous preterm delivery are considered at low risk for preterm delivery and there is good evidence that this group does not benefit from screening for, or treatment of, asymptomatic bacterial vaginosis. (A similar recommendation was made in 2001, but it referred to women of "average" risk.)