It would be impossible for any clinician to conduct an evidence-based review of every preventive strategy, and to synthesize all studies into a unified clinical recommendation. There are several organizations and academic bodies that routinely review the data and make recommendations for clinical practice.
The United States Preventive Services Task Force (USPSTF)
The U.S. Preventive Services Task Force (USPSTF) was first convened in 1984 by the U.S. Public Health Service, and published the first edition of the Guide to Clinical Preventive Services in 1989. Since 1998 the Agency for Healthcare Research and Quality (AHRQ) convenes the USPSTF, which is the leading independent panel of experts in prevention and primary care. Representatives on the panel include private-sector (non-government) family medicine physicians, general internists, pediatricians, obstetrician-gynecologists, and nursing professionals. The USPSTF conducts rigorous assessments of the scientific evidence for the effectiveness of a broad range of clinical preventive services, including screening, counseling, and chemoprophylaxis. As stated previously, the USPSTF recommendations are considered the “gold standard” for clinical preventive services.
Who are the recommendations for?
“The USPSTF evaluates the benefits of individual services based on age, gender, and risk factors for disease; makes recommendations about which preventive services should be incorporated routinely into primary medical care and for which populations; and identifies a research agenda for clinical preventive care” (AHRQ, 2008).
Recommendations issued by the USPSTF are intended for use in the primary care setting and provide clinicians with information about the evidence behind each recommendation, allowing health care providers and patients to make informed decisions about implementation. The recommendations of the USPSTF are made for asymptomatic populations.
Evidence Based Grades for USPSTF Recommendations
The USPSTF makes recommendations by assessing:
- the quality of evidence supporting a specific preventive service and;
- the magnitude of net benefit in providing the service.
The United States Preventive Services Task Force (USPSTF) updated its definitions of the grades it assigns to recommendations and now includes “suggestions for practice” associated with each grade. These definitions apply to USPSTF recommendations released after May 2007.
|USPSTF Grade Definitions for recommendations released after May 2007|
|Grade||Definition||Suggestions for Practice|
|A||The USPSTF recommends the service. There is high certainty that the net benefit is substantial.||Offer or provide this service.|
|B||The USPSTF recommends the service. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.||Offer or provide this service.|
|C||The USPSTF recommends against routinely providing the service. There may be considerations that support providing the service in an individual patient. There is at least moderate certainty that the net benefit is small.||Offer or provide this service only if other considerations support the offering or providing the service in an individual patient.|
|D||The USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.||Discourage the use of this service.|
|I||The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.||Read the clinical considerations section of USPSTF Recommendation Statement. If the service is offered, patients should understand the uncertainty about the balance of benefits and harms.|
The USPSTF has also defined the levels of certainty regarding net benefit of a service as either high,moderate, or low; visit the USPSTF website for further details on these certainty grades. The USPSTF defines certainty as “likelihood that the USPSTF assessment of the net benefit of a preventive service is correct.”
Electronic Access to USPSTF Guidelines
The AHRQ has created an electronic resource called the Electronic Preventive Services Selector (epSS) for clinicians to search for the latest USPSTF recommendations on the web or via smartphone / PDA apps.
You can look up recommendations by individual topic or individual patient demographics and risk factors. The recommendations are updated frequently, and e-mail notifications are available whenever new guidelines are released.
Read the case below and try using the epSS tool to find the answers:
The Case of Y.S.
Returning to our Case:
Y.S. is 24 year old white non-pregnant female medical student who presents to you in student health clinic today for her first visit. She has no complaints but just wanted “a check up”. She is generally healthy and had only a past medical history of acne that has resolved. She takes no medications currently and has no known drug allergies. She has no history of surgeries and no significant family history. Y.S. denies any mental health history. She has been sexually active only with her boyfriend for three years and they use condoms exclusively. Y.S. has no gynecologic or urologic complaints. This patient denies any intimate partner violence and feels she has a “good relationship” with her boyfriend. Y.S. has never smoked or used recreational drugs. Y.S. states that she no longer exercises routinely because her studies keep her very busy. She drinks one or two “Cosmos” on weekends, and does not drive a motor vehicle but her boyfriend does have a car.
According to the United States Preventive Services Task Force (USPSTF), which one of the following routine clinical preventive services is highly recommended (Grade A) because there is high certainty that the net benefit is substantial and should be offered to Y.S. based on her profile?
The correct answer is 5. The U.S. Preventive Services Task Force (USPSTF) recommends screening for Chlamydia infection for all sexually active non-pregnant young women aged 24 and younger and for older non-pregnant women who are at increased risk (Grade A). All sexually active women 24 years of age or younger, including adolescents, are at increased risk for Chlamydia infection. In addition to sexual activity and age, other risk factors for Chlamydia infection include a history of Chlamydia or other sexually transmitted infection, new or multiple sexual partners, inconsistent condom use, and exchanging sex for money or drugs. Risk factors for pregnant women are the same as for non-pregnant women. Prevalence of Chlamydia infection varies widely among patient populations. African-American and Hispanic women have a higher prevalence of infection than the general population in many communities and settings. Among men and women, increased prevalence rates are also found in incarcerated populations, military recruits, and patients at public sexually transmitted infection clinics (USPSTF, 2007).
Option a is incorrect (USPSTF, 2009). The USPSTF recommends against screening for asymptomatic bacteriuria in men and nonpregnant women (Grade D). In men and nonpregnant women, adequate evidence suggests that screening men and nonpregnant women for asymptomatic bacteriuria is ineffective in improving clinical outcomes. Potential harms associated with treatment for asymptomatic bacteriuria include adverse effects from antibiotics and development of bacterial resistance. Without evidence of benefits from screening men and nonpregnant women, the potential harms associated with overuse of antibiotics are especially significant (USPSTF, 2008).
Option b is incorrect. The USPSTF concludes that the current evidence is insufficient (Grade I) to assess the balance of benefits and harms of routine counseling of all patients in the primary care setting to reduce driving while under the influence of alcohol or riding with drivers who are alcohol-impaired. Alcohol use is involved in nearly 40% of all traffic-related fatalities. There is a critical gap in the evidence of the efficacy of behavioral counseling interventions directed to all patients in the primary care setting to reduce driving while under the influence of alcohol or riding with drivers who are alcohol-impaired (USPSTF, 2007). Y.S. does use alcohol on the weekends but does not drive. Her boyfriend does drive a car. It would be reasonable to talk with Y.S. about alcohol misuse and to avoid getting into a car if the driver is under the influence of alcohol, but the current evidence is insufficient to make this a grade A recommendation. More research needs to be done.
Option c is incorrect. The USPSTF recommends against routine serological screening for HSV in asymptomatic adolescents and adults (Grade D). The USPSTF found no evidence that screening asymptomatic adolescents and adults with serological tests for HSV antibody improves health outcomes or symptoms or reduces transmission of disease. There is good evidence that serological screening tests can accurately identify those persons who have been exposed to HSV. There is good evidence that antiviral therapy improves health outcomes in symptomatic persons (e.g., those with multiple recurrences); however, there is no evidence that the use of antiviral therapy improves health outcomes in those with asymptomatic infection. The potential harms of screening include false-positive test results, labeling, and anxiety, although there is limited evidence of any potential harms of either screening or treatment. The USPSTF determined the benefits of screening are minimal, at best, and the potential harms outweigh the potential benefits (USPSTF, 2005).
Option d is incorrect. The USPSTF concludes that the evidence is insufficient to recommend for or against behavioral counseling in primary care settings to promote physical activity (Grade I). The USPSTF found insufficient evidence to determine whether counseling patients in primary care settings to promote physical activity leads to sustained increases in physical activity among adult patients. Controlled trials of physical activity counseling in adult primary care patients were of variable quality and had mixed results. There were no completed trials with children or adolescents that compared counseling with usual care practices. Data on the feasibility and potential harms of routine physical activity counseling in primary care settings are limited. As a result, the USPSTF could not determine the balance of potential benefits and harms of routine counseling to promote physical activity in adults. The USPSTF reviewed only the literature on the effectiveness of primary care counseling to promote physical activity. It did not review the evidence for the effectiveness of physical activity to reduce chronic disease morbidity and mortality, which has been well documented in other recent reviews, or review evidence of counseling in other settings (USPSTF, 2002).
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