This is the current release of the guideline.

This guideline updates a previously published guideline: U.S. Preventive Services Task Force. Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996. Chapter 5, Screening for peripheral arterial disease. p. 63-6. [16 references]

Peripheral arterial disease

Prevention
Screening

Cardiology
Family Practice
Geriatrics
Internal Medicine
Preventive Medicine

Advanced Practice Nurses
Allied Health Personnel
Health Care Providers
Health Plans
Managed Care Organizations
Nurses
Physician Assistants
Physicians

• To summarize the U.S. Preventive Services Task Force (USPSTF) recommendations on screening for peripheral arterial disease and the supporting scientific evidence
• To update the 1996 recommendations contained in the Guide to Clinical Preventive Services, Second Edition

Asymptomatic adults seen in primary care

Considered but not Recommended

Routine screening for peripheral arterial disease using ankle brachial index, history-taking, questionnaires, or palpation of peripheral pulses

• Key Question 1: Does screening for peripheral arterial disease (PAD) lead to reduced morbidity from PAD (including claudication, amputation, impaired ambulation)?
• Key Question 2: What is the yield of screening (e.g., prevalence, sensitivity, specificity) for PAD in primary care practice?
• Key Question 3: What are the harms of screening (e.g., labeling, over-diagnosis, over treatment)?
• Key Question 4: Does treatment of people with screening-detected PAD lead to improvement in the outcomes specified in Question #1 beyond the benefits of treatment at the time of symptoms?
• Key Question 4a: Is there a subgroup of screening-detected PAD patient in whom detection of PAD results in more effective treatment of claudication beyond identification of conventional risk factors alone (e.g., through earlier or more aggressive use of treatments such as aspirin or other anti-platelet agents, lipid-lowering therapy, blood pressure treatment of lifestyle intervention)?
• Key Question 5: What are the harms of earlier treatment for PAD (i.e., side-effects of treatment)?

Searches of Electronic Databases

Note from the National Guideline Clearinghouse (NGC): A targeted review of the literature was prepared by the Lewin Group for the Agency for Healthcare Research and Quality (AHRQ) for use by the U.S. Preventive Services Task Force (USPSTF) (see the "Companion Documents" field).

Search Strategy

The literature search was guided by an analytic framework developed specifically for peripheral arterial disease (PAD) by the USPSTF. Specifically, this review focused on PAD outcomes and did not examine PAD as a risk factor for coronary heart disease (CHD).

The search strategy included a review of English language articles identified from Pubmed, the Cochrane Library, and the National Guideline Clearinghouse, published between 1994 and 2003. The search excluded letters, editorials, and narrative reviews. Studies of symptomatic (i.e., PAD or intermittent claudication) populations were also excluded from this search.

Abstracts were reviewed to determine which articles addressed the Key Questions. One reviewer examined the abstracts with the instruction to retain all that were clearly in-scope and those with potential or ambiguous relevance. These abstracts were then reviewed by a senior staff member for relevance.

Upon finalizing this report, a subsequent bridge search was conducted of literature published between January 2004 and June 2005. No relevant studies were identified.

• Key question #1: One randomized controlled trial
• Key question #2: No new evidence meeting search criteria was identified.
• Key question #3: No new evidence meeting search criteria was identified.
• Key question #4: One cross-sectional study
• Key question #4a: One fair quality study
• Key question #5: No new evidence meeting search criteria was identified.

Weighting According to a Rating Scheme (Scheme Given)

The U.S. Preventive Services Task Force (USPSTF) grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor):

Good

Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.

Fair

Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.

Poor

Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.

Systematic Review

Not stated

Balance Sheets
Expert Consensus

When the overall quality of the evidence is judged to be good or fair, the U.S. Preventive Services Task Force (USPSTF) proceeds to consider the magnitude of net benefit to be expected from implementation of the preventive service. Determining net benefit requires assessing both the magnitude of benefits and the magnitude of harms and weighing the two.

The USPSTF classifies benefits, harms, and net benefits on a 4-point scale: "substantial," "moderate," "small," and "zero/negative."

"Outcomes tables" (similar to "balance sheets") are the USPSTF's standard resource for estimating the magnitude of benefit. These tables, prepared by the topic teams for use at USPSTF meetings, compare the condition specific outcomes expected for a hypothetical primary care population with and without use of the preventive service. These comparisons may be extended to consider only people of specified age or risk groups or other aspects of implementation. Thus, outcomes tables allow the USPSTF to examine directly how the preventive service affects benefits for various groups.

When evidence on harms is available, the topic teams assess its quality in a manner like that for benefits and include adverse events in the outcomes tables. When few harms data are available, the USPSTF does not assume that harms are small or nonexistent. It recognizes a responsibility to consider which harms are likely and judge their potential frequency and the severity that might ensue from implementing the service. It uses whatever evidence exists to construct a general confidence interval on the 4-point scale (e.g., substantial, moderate, small, and zero/negative).

Value judgments are involved in using the information in an outcomes table to rate either benefits or harms on the USPSTF's 4-point scale. Value judgments are also needed to weigh benefits against harms to arrive a rating of net benefit.

In making its determinations of net benefit, the USPSTF strives to consider what it believes are the general values of most people. It does this with greater confidence for certain outcomes (e.g., death) about which there is little disagreement about undesirability, but it recognizes that the degree of risk people are willing to accept to avert other outcomes (e.g., cataracts) can vary considerably. When the USPSTF perceives that preferences among individuals vary greatly, and that these variations are sufficient to make trade-off of benefits and harms a "close-call," then it will often assign a C recommendation (see the "Recommendation Rating Scheme" field). This recommendation indicates the decision is likely to be sensitive to individual patient preferences.

The USPSTF uses its assessment of the evidence and magnitude of net benefit to make recommendations. The general principles the USPSTF follows in making recommendations are outlined in Table 5 of the companion document cited below. The USPSTF liaisons on the topic team compose the first drafts of the recommendations and rationale statements, which the full panel then reviews and edits. Recommendations are based on formal voting procedures that include explicit rules for determining the views of the majority.

From: Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow, CD, Teutsch SM, Atkins D. Current methods of the U.S. Preventive Services Task Force: a review of the process. Methods Work Group, Third U.S. Preventive Services Task Force. Am J Prev Med 2001 Apr;20(3S):21-35.

The U.S. Preventive Services Task Force (USPSTF) grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms):

A

The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.

B

The USPSTF recommends that clinicians provide [this service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms.

C

The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation.

D

The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits.

I

The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that [the service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined.

A formal cost analysis was not performed and published cost analyses were not reviewed.

Comparison with Guidelines from Other Groups
External Peer Review
Internal Peer Review

Peer Review. Before the U.S. Preventive Services Task Force (USPSTF) makes its final determinations about recommendations on a given preventive service, the Evidence-based Practice Center and the Agency for Healthcare Research and Quality send a draft systematic evidence review to 4 to 6 external experts and to federal agencies and professional and disease-based health organizations with interests in the topic. They ask the experts to examine the review critically for accuracy and completeness and to respond to a series of specific questions about the document. After assembling these external review comments and documenting the proposed response to key comments, the topic team presents this information to the Task Force in memo form. In this way, the Task Force can consider these external comments and a final version of the systematic review before it votes on its recommendations about the service. Draft recommendations are then circulated for comment from reviewers representing professional societies, voluntary organizations, and Federal agencies. These comments are discussed before the whole USPSTF before final recommendations are confirmed.

Recommendation of Others. Recommendations for screening for peripheral arterial disease from the following groups were discussed: the American Diabetes Association (ADA), the American Academy of Family Physicians (AAFP), the American Heart Association (AHA), and the Society for Interventional Radiology (SIR).

The U.S. Preventive Services Task Force (USPSTF) grades its recommendations (A, B, C, D, or I) and the quality of the overall evidence for a service (good, fair, poor). The definitions of these grades can be found at the end of the "Major Recommendations" field.

The USPSTF recommends against routine screening for peripheral arterial disease (PAD). D recommendation

The USPSTF found fair evidence that screening with ankle brachial index can detect adults with asymptomatic PAD. The evidence is also fair that screening for PAD among asymptomatic adults in the general population would have few or no benefits because the prevalence of PAD in this group is low, and because there is little evidence that treatment of PAD at this asymptomatic stage of disease, beyond treatment based on standard cardiovascular risk assessment, improves health outcomes.

The USPSTF found fair evidence that screening asymptomatic adults with the ankle brachial index could lead to some small degree of harm, including false-positive results and unnecessary work-ups. Thus, the USPSTF concludes that, for asymptomatic adults, harms of routine screening for PAD exceed benefits.

Clinical Considerations

• The ankle brachial index, a ratio of Doppler-recorded systolic pressures in the lower and upper extremities, is a simple and accurate noninvasive test for the screening and diagnosis of PAD. The ankle brachial index has demonstrated better accuracy than other methods of screening, including history-taking, questionnaires, and palpation of peripheral pulses. An ankle-brachial index value of less than 0.90 (95% sensitive and specific for angiographic PAD) is strongly associated with limitations in lower extremity functioning and physical activity tolerance.
• Smoking cessation and lipid-lowering agents improve claudication symptoms and lower extremity functioning among patients with symptomatic PAD. Smoking cessation and physical activity training also increase maximal walking distance among men with early PAD. Counseling for smoking cessation, however, should be offered to all patients who smoke, regardless of the presence of PAD. Similarly, physically inactive patients should be counseled to increase their physical activity, regardless of the presence of PAD.

Definitions:

Strength of Recommendations

The USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms):

A

The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.

B

The USPSTF recommends that clinicians provide [this service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms.

C

The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation.

D

The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits.

I

The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that [the service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined.

Strength of Evidence

The U.S. Preventive Services Task Force (USPSTF) grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor):

Good

Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.

Fair

Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.

Poor

Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.

None provided

The type of evidence supporting the recommendations is identified in the "Major Recommendations" field.

Appropriate screening for peripheral arterial disease

Potential harms of screening include false-positive results, labeling, and the adverse events associated with an angiographic workup, including contrast-related events, arterial perforations, hematomas, thromboses, and distal embolizations. The harms of treatment include the adverse events associated with medical (antithrombotic medications) and surgical treatments (angioplasty, femoral bypass procedures).

Recommendations made by the U.S. Preventive Services Task Force are independent of the U.S. Government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

Staying Healthy

Effectiveness
Patient-centeredness

Not applicable: The guideline was not adapted from another source.

2005 Aug

United States Preventive Services Task Force - Independent Expert Panel

Agency for Healthcare Research and Quality

U.S. Preventive Services Task Force (USPSTF)

The U.S. Preventive Services Task Force has an explicit policy concerning conflict of interest. All members and evidence-based practice center (EPC) staff disclose at each meeting if they have an important financial conflict for each topic being discussed. Task Force members and EPC staff with conflicts can participate in discussions about evidence, but members abstain from voting on recommendations about the topic in question.

From: Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow, CD, Teutsch SM, Atkins D. Current methods of the U.S. Preventive Services Task Force: a review of the process. Methods Work Group, Third U.S. Preventive Services Task Force. Am J Prev Med 2001 Apr;20(3S):21-35.

This is the current release of the guideline.

This guideline updates a previously published guideline: U.S. Preventive Services Task Force. Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996. Chapter 5, Screening for peripheral arterial disease. p. 63-6. [16 references]

This NGC summary was completed by ECRI on June 10, 2005. The information was verified by the guideline developer on June 17, 2005.