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Screening for Peripheral Artery Disease Draft Research Plan
Topic Group for Stakeholders Webinar
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Following is the text version of the Webinar presentation on the draft Research Plan for Screening for Peripheral Artery Disease.
Slide 1
Peripheral Artery Disease Draft Research Plan
Topic Group for Stakeholders Webinar
December 15, 2011
Timothy Wilt, MD, MPH
Professor, Department of Medicine, University of Minnesota Minneapolis, VA Medical Center
USPSTF Member
Slide 2
Objectives
- Describe the purpose of this new pilot process.
- Walk through the USPSTF recommendation process.
- Discuss the draft research plan.
- Talk about the next steps.
- Q & A.
Slide 3
Pilot Process
The U.S. Preventive Services Task Force...
- Topic Group for Stakeholders or TOPS.
- Increase transparency of USPSTF recommendation process.
- Engage with stakeholders and public.
- Additional engagement points:
- Suggest peer reviewers for the draft evidence report.
- Provide feedback on the draft recommendation statement.
- Dissemination and implementation activities of final recommendation.
Slide 4
USPSTF Overview
- Makes recommendations on clinical preventive services to primary care clinicians:
- The USPSTF scope for clinical preventive services include:
- Screening tests
- Counseling
- Preventive medications
- Services are offered in a primary care setting.
- Recommendations apply to adults & children with no signs or symptoms.
- The USPSTF scope for clinical preventive services include:
- Makes recommendations based on rigorous review of existing peer-reviewed evidence:
- Does not conduct the research studies, but reviews & assesses the research.
- Evaluates benefits & harms of each service based on factors such as age & sex.
- Is an independent panel of non-Federal experts in prevention & evidenced-based medicine.
Slide 5
Recommendation Process
Stages of Development chart. The first four stages are as follows:
- Draft Research Plan Development: The Task Force topic work group, with support from the Evidence-based Practice Center (EPC), creates a draft research plan that guides the recommendation process.
- Public Comment Opportunity: The draft research plan is posted on the USPSTF Web site for public comment. The Task Force reviews the comments, addresses them as appropriate, and creates a final research plan.
- Evidence Review: EPC independently gathers and reviews the available published evidence. Evidence review critiqued by external national subject matter experts. EPC presents the evidence to the USPSTF topic workgroup.
- Draft Recommendation Development: USPSTF topic workgroup discusses the evidence and drafts a preliminary recommendation.
Slide 6
Recommendation Process (continued)
Stages of Development chart. The last four stages are as follows:
- Full Task Force Review: Evidence report and draft recommendation statement are presented to the full Task Force. All members discuss draft recommendation statement. Topic workgroup then drafts the full recommendation language, including clinical considerations and discussion.
- Public Comment Opportunity: The evidence report is finalized and published. The draft recommendation is posted on the USPSTF Web site for public comment. Task Force members review all comments, address them as appropriate, and finalize the recommendation.
- Task Force Vote: Task Force votes to ratify the final recommendation statement.
- Final Recommendation Published: Most final recommendations are published in Annals of Internal Medicine, Pediatrics, or Annals of Family Medicine. All recommendations and supporting evidence reports are posted on the Task Force Web site.
Slide 7
Timing
- Scoping began summer 2011.
- Next step is to finalize research plan.
- Plan to develop the draft recommendation statement summer 2012.
- Final recommendation slated for as early as late summer 2013.
Slide 8
Draft Research Plan Overview
- Comprised of three distinct components:
- Analytic framework, which is a visual depiction of the chain of logic that the evidence must support to establish whether a net benefit exists for a given preventive service.
- Key and contextual questions, that serve as the basic roadmap to guide the evidence review.
- Specific search criteria that will be applied when searching for evidence to answer the proposed questions.
Slide 9
Proposed Analytic Framework
This figure depicts the key questions for the proposed research plan for screening for peripheral artery disease (PAD). In general, the figure illustrates how screening for PAD with an ankle brachial index may result in either a positive or negative test result. Among patients with a positive test result, screening and subsequent treatment may result in improved intermediate cardiovascular disease outcomes such as improved blood pressure and cholesterol, and/or long-term health outcomes such as reduced mortality, reduced PAD morbidity (e.g., symptom prevention, ambulation, patient function, amputation), and reduced cardiovascular morbidity (e.g., myocardial infarction, stroke). Also, adverse events may occur at any point after the screening or intervention is administered.
Slide 10
Proposed Key Questions
- Does screening for peripheral artery disease (PAD) with an ankle brachial index (ABI) in asymptomatic adults lead to reduced mortality, reduced morbidity from PAD (e.g., onset of symptoms, amputation, impaired ambulation, impaired function), or reduced cardiovascular morbidity (e.g., myocardial infarction, stroke)?
- Does the effectiveness of screening for PAD vary by subgroup (i.e., age, sex, race, risk factors)?
- What is the diagnostic accuracy (e.g., sensitivity, specificity, positive predictive value, negative predictive value) of ABI as a screening test for PAD in asymptomatic adults?
- Does the diagnostic accuracy of ABI screening vary by subgroup (i.e., age, sex, race, risk factors)?
- What are the harms of screening (e.g., overdiagnosis, overtreatment)?
- Do the harms of screening vary by subgroup (i.e., age, sex, race, risk factors)?
Slide 11
Proposed Key Questions (continued)
- A. Does treatment of PAD in asymptomatic adults lead to improvement in patient outcomes (i.e., cardiovascular disease [CVD] intermediate or health outcomes)?
- Does the effectiveness of earlier treatment of PAD vary by subgroup (i.e., age, sex, race, risk factors)?
- B. Does treatment of PAD in asymptomatic adults lead to improved patient outcomes beyond the benefits of treatment in symptomatic adults, or beyond the benefits of treatment in persons with identified conventional risk factors alone (i.e., diabetes, smoking, hypertension, hyperlipidemia)?
- Does the effectiveness of earlier treatment of PAD vary by subgroup (i.e., age, sex, race, risk factors)?
- What are the harms of treatment of screen-detected PAD?
- Do the harms of early treatment of PAD vary by subgroup (i.e., age, sex, race, risk factors)?
Slide 12
Proposed Contextual Questions
Note: Contextual questions represent issues for which the USPSTF needs a valid but not necessarily systematic summary of current research in order to provide context for its recommendations.
- What is the co-occurrence of PAD and other CVD (i.e., coronary artery disease, cerebrovascular disease)?
- What proportion of patients with PAD have CVD risk factors (i.e., diabetes, smoking, hypertension, hyperlipidemia)?
Slide 13
Proposed Contextual Questions (continued)
- What proportion of asymptomatic adults have an abnormal ABI in primary care?
- What proportion of patients with an abnormal ABI receive additional diagnostic testing?
- What proportion of abnormal ABI results are >1.30 or 1.40?
- What proportion of patients with ABI results >1.30 or 1.40 have PAD?
- What is the ability of ABI to predict CVD events (e.g., myocardial infarction, stroke)? Does ABI predict CVD events independent of traditional risk factors?
Slide 14
Proposed Research Approach
| Inclusion | Exclusion | |
|---|---|---|
| Population | Screening (KQs 1–3): Community-dwelling, asymptomatic adults (may include populations with atypical symptoms not recognized as PAD); unselected, primary care relevant populations or primary care relevant populations selected based on risk (e.g., age, smoking history, hypertension, hyperlipidemia)
Treatment (KQs 4–5): Asymptomatic adults (this may include populations with atypical symptoms not recognized as PAD) |
Symptomatic adults, populations exclusively comprised of persons with known CVD or diabetes |
| Setting | KQs 1–3: Primary care, outpatient settings (ambulatory care)
KQs 4–5: No restrictions |
Hospital/inpatient settings, long-term care facilities, vascular clinics |
| Disease/condition | Lower extremity PAD secondary to atherosclerosis | |
| Screening (KQs 1–3) | Resting Ankle Brachial Pressure (ABI) | History taking, physical examination, questionnaires, digital subtraction arteriography, duplex ultrasonography, magnetic resonance angiography, CT angiography, toe pressure measurement, treadmill testing, pulse oximetry, near-infrared spectroscopy, all invasive diagnostic testing |
Slide 15
Proposed Research Approach (continued)
| Inclusion | Exclusion | |
|---|---|---|
| Treatment or management interventions (KQs 4–5) | Interventions primarily aimed at CVD reduction: interventions for smoking cessation, cholesterol lowering, glycemic control, weight loss, blood pressure control, antiplatelet therapy | Vitamins or nutritional or herbal supplements
Interventions aimed only at symptomatic persons or persons with critical limb ischemia: pharmacologic symptom management (pentoxyfylline, cilostazol, prostaglandins); nonpharmacologic symptom management (lower extremity rehab, supervised exercise training and therapy); vascular intervention (angioplasty, stenting, bypass) |
| Comparisons | KQ 1: No screening
KQ 2: Reference standard KQ 4: True control group (placebo, no intervention, or usual care), intervention/treatment at later or symptomatic stages of disease (versus treatment at earlier or asymptomatic stages) |
|
| Outcomes | KQ 1: Mortality (all-cause, CVD related), PAD morbidity (ambulation, patient function, amputation), reduced cardiovascular morbidity (MI, CVA)
KQ 2: Sensitivity, specificity, PPV, NPV for PAD, incidence or prevalence KQ 4: Cardiovascular intermediate outcomes (e.g., blood pressure, cholesterol), lower extremity symptom prevention, functional improvement, cardiovascular health outcomes (e.g., myocardial infarction, cerebrovascular accident) |
Patient satisfaction
Cost-related outcomes (for screening and treatment) |
Slide 16
Proposed Research Approach (continued)
| Inclusion | Exclusion | |
|---|---|---|
| Harms | KQ 3: Adverse outcomes related to diagnostic inaccuracy
KQ 5: Serious adverse events (e.g., death, serious adverse drug reactions), unexpected medical attention (e.g., emergency department visits, hospitalizations) |
Patient satisfaction |
| Study Designs | KQs 1, 4: Good-quality systematic reviews, randomized (RCT) or clinically controlled trials (CCTs)
KQ 2: Good-quality systematic reviews, diagnostic accuracy studies KQs 3, 5: Good-quality systematic reviews, trials (RCT or CCT), cohort or case-control studies |
Poor-quality studies based on established design-specific quality criteria;
KQ 2: Case-control diagnostic accuracy studies KQ 4: Less than 3 months follow-up |
| Language | English only | Non-English languages |
| Data Sources | KQs 1, 2, 4: MEDLINE and the Cochrane Central Registry of Controlled Trials
KQs 3, 5: MEDLINE, the Cochrane Central Registry of Controlled Trials, grey literature and non-database searches (may include disease-based registries, U.S. Food and Drug Administration for pharmacologic interventions, selected conferences such as the Society for Vascular Medicine, American Heart Association), and ClinicalTrials.gov |
|
| Search Dates | KQs 1, 2, 3: Inception of the database to December 31, 2011 (an additional bridge search may be conducted in spring 2012 to capture additional evidence published between 1/1/12 and 3/31/12)
KQs 4, 5: January 1, 1990 to December 31, 2011 (an additional bridge search may be conducted in spring 2012 to capture additional evidence published between 1/1/12 and 3/31/12) |
Slide 17
Type of Feedback Requested
- Does the Draft Research Plan scope the topic correctly?
- Is the USPSTF asking the most critical questions?
- Are the appropriate benefits and harms being considered?
- Are the inclusion and exclusion criteria appropriate?
Slide 18
Submitting Feedback
- Go to: www.uspreventiveservicestaskforce.org/tfcomment.htm.
- Click on the link to submit comments on screening for PAD draft research plan.
- Follow the steps to submit feedback.
Slide 19
Questions?
If you have general USPSTF questions please contact Bob Cosby at Robert.Cosby@ahrq.hhs.gov.
Slide 20
Thank you for your interest.
www.USPreventiveServicesTaskForce.org
Current as of December 2011
Internet Citation:
Screening for Peripheral Artery Disease Draft Research Plan: Topic Group for Stakeholders Webinar (Text Version). U.S. Preventive Services Task Force. December 2011. http://www.uspreventiveservicestaskforce.org/uspstf12/pad/padslides.htm
USPSTF Program Office |
