# Presentation: 630869

## US Preventive Services Task Force

- Kenneth Lin, MD, Medical Officer AHRQ
- Diana Petitti, MD, MPH, Vice Chair USPSTF
- Tracy Wolff, MD, MPH, Medical Officer AHRQ

## US Preventive Services Task Force

**Independent **panel of experts in primary care and prevention, multidisciplinary
- Systematically reviews evidence for clinical preventive services implemented in a primary care setting
- Makes recommendations on clinical preventive services in  populations **without recognized signs or symptoms of illness**
- AHRQ is mandated to convene and support USPSTF
- Scientific support from Evidence-Based Practice Centers
- Liaisons from primary care subspecialty societies and  federal agencies

**Notes:**
Presenter: Tracy

## Target Audiences 

- Primary Care Clinicians and the Systems in which they function (including other clinicians)
- Academicians and Researchers
- Quality Improvement Professionals and makers of tools that affect primary care practice
- Health Care Policymakers and System Leaders
- Employers and other Healthcare Purchasers
- Members of the Public

## History of the Task Forces

**1976 - Canadian Task Force on PHE**
**1984 - USPSTF established by PHS**
**1996 – Community Task Force**
**1998 - 3rd USPSTF reconvened by AHRQ**
**2001 - Standing USPSTF Task Force**

**Notes:**
Where did the task force come from?
(Read above) PHE = periodic health exam
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## Structure of USPSTF

**Notes:**
Here is a graphic that explains how AHRQ and the task force work together.  The Task force is an independent body that receives technical support from AHRQ, a federal agency.  The evidence-based centers (EPC) also provide technical support to AHRQ and the task force through systematic reviews of the evidence.

## Task Force Activities

- Provide **evidence-based** scientific reviews of preventive health services for use in **primary healthcare delivery settings**
-  Age- and risk-factor specific recommendations for routine practice
- Primary and Secondary Prevention Recommendations:
- Screening tests
- Counseling
- Preventive medications

**Notes:**
Again the task force (read above)
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## Recommendations Released in 2007 and 2008

- ASA/NSAIDs to Prevent Colorectal CA
- Chlamydia: Screening
- Carotid Artery Stenosis: Screening
- HTN in Adults
- Lipid Disorders in Children
- Motor Vehicle Occupant Injuries: Counseling
- Sickle Cell Disease in Newborns: Screening
- Prostate Cancer

- Asymptomatic Bacteruria: Screening
- BV in Pregnancy
- Congenital Hypothyroidism
- COPD Screening
- Diabetes Type II: Screening
- Gestational DM: Screening
- Newborn Hearing: Screening
- PKU: Screening
- Adult Lipids: Screening

## USPSTF Topics in Progress

- ASA to prevent CVD
- Breast CA – screening & PM
- Breastfeeding
- Cervical CA screening
- Colorectal cancer screening
- CHD – risk factor screening
- Dementia
- Depression screening
- Falls in the Elderly
- Oral cancer screening
- Tobacco counseling
- Hepatitis B screening

- Folic Acid for NTD Prevention
- Hyperbilirubinemia – newborn screening
- Lung Cancer
- Multivitamins and supplements
- Obesity
- Osteoporosis – Screening
- Physical Activity
- Skin cancer – Screening
- STI – counseling
- Vision in Older Adults

## What’s new?

- Updating previous recommendations
- Addressing geriatric and child health recommendations
- Federal Register notice for new topic nominations
- Implementation –
- Tools
- Pocket guide
- PDA
- Website
- New recommendation statement format

**Notes:**
Epc do methods piece on updating
AHRQ working on an in-house process
Rubber stamping vs. archive
Staged reviews
With CDC: HIV
Childhood obesity
Newborn screening?

## Examples of USPSTF Resources

- Annual Pocket Guide to Clinical Preventive Services
- One-page clinical summary of RS
- Adult Preventive Services timeline
*e*PSS
- Publication of Recommendations in academic journals – *Annals of Internal Medicine, Pediatrics*
- Partnerships with professional societies, ePocrates, Medscape
- Patient brochures

## Employers and Policy Makers

*A Purchaser’s Guide to Clinical Preventive Services* – with the National Business Group on Health (NBGH) and CDC
*Employer’s Guide to Health Improvement and Preventive Services* – with NBGH and Robert Wood Johnson Foundation

- _[www.preventiveservices.ahrq.gov](http://www.preventiveservices.ahrq.gov/)_
- Please visit our booth in the m***AHRQ***et Place Café for examples of USPSTF resources
- Please also attend:
- Session #66 USPSTF Making a Difference in Clinical Care – Tues, Sept. 9th 10-1130 AM

**Evidence and the USPSTF**

## Steps in the Recommendation Development Process

**Define questions and outcomes of interest using analytic framework**
- Define and retrieve relevant evidence
- Evaluate QUALITY of individual studies
- Synthesize and judge strength of overall evidence and draw conclusion about CERTAINTY
- Determine balance of benefits and harms
- Link recommendation to magnitude and certainty of net benefits

**Notes:**
Here are the steps the task force follows in its development of recommendations.  I am going to go through these steps individually.  The first step is defining the question and the outcome of interest for a topic (for example, prostate cancer).
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## Step 1: Analytic Framework on Screening for a Disease

**Notes:**
The task force first develops an analytic framework for a topic. The framework not only provides a graphical depiction of the process, it makes explicit a  number of essential considerations::
The target population, intervention, comparison and most important outcomes. 
It depicts intermediate outcomes that may mediate the effects on or serve as surrogates for the more distal outcome.
It identifies discrete questions which can be answered through a review of the evidence. 
It explicitly depicts downstream consequences of the initial intervention and possible subsequent interventions – the adverse as well as beneficial effects, and all of these together determine the overall balance of benefits and harms. 
Finally, it distinguishes studies which provide a direct link between an intervention and an outcome (top arrow) from less direct linkages between screening and reduced morbidity

From this analytic framework the task force develops key questions.
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## Example: Analytic Framework for Prostate Cancer Screening

**Early Prostate**
**Cancer**

**Reduced prostate **
**cancer morbidity,**
**mortality**

**Asymptomatic**
**Men**

**Screen:**
**PSA, DRE**

**Treat**
**radiation,**
**prostatectomy****   **
**                    ****3**

**Adverse effects**
**of screening:**
**false positive, false negative, inconvenience,**
**labeling**

**Adverse effects of Rx:**
**Impotence, incontinence,**
**death, overtreatment**

**1**

**2**

**4**

**5**

**Notes:**
Here is one example of an analytic framework for prostate cancer that includes screening of asymptomatic men with psa/dre to detect early prostate cancer, and adverse effects. Note that adverse effects can be associated with the screening process as well as harms from treatment.
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## Steps in the Recommendation Development Process

- Define questions and outcomes of interest using analytic framework
**Define and retrieve relevant evidence**
- Evaluate QUALITY of individual studies
- Synthesize and judge strength of overall evidence and draw conclusion about CERTAINTY
- Determine balance of benefits and harms
- Link recommendation to magnitude and certainty of net benefits

**Notes:**
The next step is to define and retrieve relevant evidence
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## Step 2: Define & Retrieve Relevant Evidence

- Create inclusion/exclusion criteria based on the key questions from the analytic framework
- Interventions (eg screening, counseling, meds)
- Outcomes
- Populations
- Setting (generalizable to primary care)
- Time period
- Types of studies
- Sources of evidence
- PubMed, Cochrane, other database searches
- “Reference mining”
- Hand searching topic-relevant specialty journals
- Recommendations from experts

**Notes:**
Steps in the process of defining and retrieving relevant evidence are (read above). Inclusion and exclusion criteria should be established before beginning the review.
The goal of this step is to obtain quality evidence about the amount of harm and the amount of benefit for screening (or chemoprophylaxis or counseling) for a condition.
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## Steps in the Recommendation Development Process

- Define questions and outcomes of interest using analytic framework
- Define and retrieve relevant evidence
**Evaluate quality of individual studies**
- Synthesize and judge strength of overall evidence and make conclusion about CERTAINTY
- Determine balance of benefits and harms
- Link recommendation to magnitude and certainty of net benefits

**Notes:**
The next step is to evaluate the quality of individual studies
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## Step 3: Evaluate Quality of Individual Studies

_**Good:**_
- Evaluates relevant available screening tests
- Uses a credible reference standard
- Interprets reference standard independently of screening test
- Large sample size, ~ 100 broad spectrum patients
_**Fair:**_
- Evaluates relevant available screening tests
- Uses reasonable although not best standard;
- Interprets reference standard independent of screening test;
- Moderate sample size, ~ 50-100 “medium” spectrum patients
_**Poor:**_ Has fatal flaw such as:
- Uses inappropriate reference standard
- Screening test improperly administered
- Biased ascertainment of reference standard
- Very small sample size or very narrow selected spectrum of patients.

**Notes:**
The task force uses a good, fair, poor scale for individual studies (read above)
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## Steps in the Recommendation Development Process

- Define questions and outcomes of interest using analytic framework
- Define and retrieve relevant evidence
- Evaluate quality of individual studies
**Synthesize and judge strength of overall evidence and make conclusion about CERTAINTY**
- Determine balance of benefits and harms
- Link recommendation to magnitude and certainty of net benefits

**Notes:**
The next step is to synthesize and judge the strength of the overall evidence.
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## Step 4: Synthesize and Judge Strength of Overall Evidence

- Evidence reports
- Evidence tables summarizing studies
- Narrative discussing overall strength of evidence
- Meta-analysis
- Modeling
- Decision analysis
- Projected outcomes table
- Systematic reviews from others

**Notes:**
The task force uses several sources of information for synthesizing and judging the strength of the overall evidence.  These sources include (read above)
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## Critical Appraisal Questions

- Do the studies have the appropriate research design to answer the key question?
- To what extent are the existing studies high quality?
- To what extent are the results of the studies generalizable (or “applicable”) to the general US primary care population and situation?
- How many studies have been conducted that address the key question?  How large are the studies?
- How consistent/coherent are the results of the studies?
- Are there additional factors that assist us in drawing conclusions about the certainty of the evidence? (e.g., presence or absence of dose-response effects; fit within a biologic model)

## Step 4: Synthesize & Judge Strength of Evidence for Each Key Question

_**Convincing**_**:**  Well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes
_**Adequate:**_ Evidence sufficient to determine effects on health outcomes, but limited by number, quality, or consistency of studies, generalizability to routine practice, or indirect nature of the evidence.
_**Inadequate**_**:** Insufficient evidence to determine effect on health outcomes due to 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

**Notes:**
The task force uses this scale to rate the strength of evidence for each key question
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## Step 4: Synthesize and Judge Strength of Overall Evidence: Certainty

**Definition:** The U.S. Preventive Services Task Force defines certainty as **“**likelihood that the USPSTF assessment of the net benefit of a preventive service is correct**”.** The net benefit is defined as benefit minus harm of the preventive service as implemented in a general, primary care population.  The USPSTF assigns a certainty level based on the nature of the overall evidence available to assess the net benefit of a preventive service.

## Levels of Certainty: High, Moderate, or Low

**High:**  This conclusion is unlikely to be strongly affected by the results of future studies.
**Moderate:  **As more information becomes available, the magnitude or direction of the observed effect could change, and this change may be large enough to alter the conclusion.
**Low:**  The available evidence is insufficient to assess effects on health outcomes.

## Steps in the Recommendation Development Process

- Define questions and outcomes of interest using analytic framework
- Define and retrieve relevant evidence
- Evaluate quality of individual studies
- Synthesize and judge strength of overall evidence and make conclusion about CERTAINTY
**Determine balance of benefits and harms**
- Link recommendation to magnitude and certainty of net benefits

**Notes:**
The next step is to determine the balance of benefits and harms of screening for a condition
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## Step 5: Determine Balance of Benefits and Harms

- _Estimate Magnitude of Net Benefit_
- Benefits of Service – Harms of Service = Net Benefit
- 4 categories of Net Benefit:
**	****Zero/Negative**
**	****Small**
**	****Moderate**
**	****Substantial**

**Notes:**
Simply put the task force estimates the net benefit of screening for a condition by subtracting the harms of screening from the benefits of screening.  
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## Estimating Benefits: Projected Outcomes Table (COPD)

|  |      NHANES I | EPC pooled analysis |  |  |
| --- | --- | --- | --- | --- |
|  | Number / 10,000 with FEV1<50% predicted | Number of patients prevented from having >=1 COPD exacerbation |         Number needed to screen (NNS) |  |
| Current smoker | 207 | 12 | 833 |  |
| Previous smoker | 216 | 13 | 960 |  |
| Never smoker | 95 | 5 | 2000 |  |
| Age 40-49 | 80 | 4 | 2500 |  |
| Age 50-59 | 260 | 15 | 667 |  |
| Age 60-69 | 370 | 22 | 455 |  |
| Age 70-74 | 420 | 25 | 400 |  |

**Notes:**
This is our best estimate of the benefits

## Estimating Harms: Issues

- Harms of prevention are real but hard to quantify
- Include psychological and physical consequences of false-positives, false-negatives, “labeling,” overtreatment of “pseudodisease”
- Opportunity costs
- Time and effort required by patients and the health care system (may be substantial)
- Magnitude and duration of harm subjective, hard to compare to benefits
- NNH for well-defined harms (eg GI bleeds from ASA)

**Notes:**
How does the task force assess harms?  (Read above)
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## Assessing Magnitude of Net Benefit  

- No explicit criteria for magnitude
*Substantial* *benefit* : impact on high burden *or* major effect on uncommon outcome
- Problems: requires evidence on harms and common metric for benefit and harms
- Always requires judgment

**Notes:**
How does the task force assess the magnitude of benefit of screening for a condition?  (read above)
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## Steps in the Recommendation Development Process

- Define questions and outcomes of interest using analytic framework
- Define and retrieve relevant evidence
- Evaluate quality of individual studies
- Synthesize and judge strength of overall evidence and make conclusion about CERTAINTY
- Determine balance of benefits and harms
**Link recommendation to magnitude and certainty of net benefits**

**Notes:**
The next step is to link the net benefits to a recommendation about a preventive services 
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## Step 6: Link recommendation to net benefits: USPSTF Grades of Recommendations

| Certainty of Net Benefit | Magnitude of Net Benefit |  |  |  |
| --- | --- | --- | --- | --- |
|  | Substantial | Moderate | Small | Zero/negative |
| High | A | B | C | D |
| Moderate | B | B | C | D |
| Low | Insufficient |  |  |  |

**Notes:**
The task force uses this simplified grid to determine the grade of the recommendation.  I will discuss in the next slide exactly what is meant by the letter grade.  But I first want to explain the grid in the slide.  The task force uses two measures, strenght of overall evidence (good fair poort) and the estimate of net benefit (benefit  minus harms) and using this grid deteremines a letter grade.  For example if the evidence is good about the effectiveness of screening for condition x but there is more harms than benefits (negative net benefit) than the task force give a D recommendation
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## Step 6: Link recommendation to net benefits: USPSTF Wording of Recommendations

**Step 6: **Link recommendation to net benefits: **USPSTF Wording of Recommendations**

| Grade | Grade Definition | Suggestion 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 moderate or high certainty that the net benefit is small. | Offer or provide this service only if there are other considerations that support 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 “Clinical Considerations” section of USPSTF Recommendation Statement. If offered the service, patients should understand the uncertainty about the balance of benefits and harms. |

**Notes:**
The task force uses letter grades for their recommendations.  (Read above)
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- Diana’s Slides

- Questions?