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Acknowledgement

Understanding the Methods Used by the U.S. Preventive Services Task Force in Developing Recommendations. Acknowledgement.

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Acknowledgement

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  1. Understanding the Methods Used by the U.S. Preventive Services Task Force in Developing Recommendations

  2. Acknowledgement • These materials were developed under an agreement between the Health Research & Education Trust and George F. Sawaya, MD as part of the “Knowledge Transfer/Implementation- Outreach to Health Professionals” project, no. HHSA 290200900014C sponsored by the Agency for Healthcare Quality and Research. • Dr. Sawaya is Professor of Obstetrics, Gynecology and Reproductive Sciences and Epidemiology and Biostatistics at the University of California, San Francisco. He was a member of the U.S. Preventive Services Task Force from 2004-2008. • The information herein was current as of August 2010 as per the USPSTF website www.uspreventiveservicestaskforce.org/about.htm

  3. Target Setting and Audience • The materials presented herein are devised for a large-group lecture setting. • The materials are applicable for use at all levels of training: undergraduate medical education, graduate medical education, and continuing medical education. • These materials are linked to a teaching module appropriate for an instructor-led small-group setting.

  4. Educational Objective To understand the methods used by the U.S. Preventive Services Task Force (USPSTF) to arrive at recommendations, using recent changes to the USPSTF breast cancer screening recommendations as an example.

  5. Case • A 40-year-old woman presents to your clinic for a periodic health examination. She is healthy and has no risk factors for any particular diseases. She does not smoke, is sexually active and is not pregnant. You note that the US Preventive Services Task Force recommends screening for the following diseases: cervical cancer, hypertension, alcohol misuse and obesity. Mammography is not recommended. She has read about the mammography controversy and wants to know more about the benefits and harms.

  6. Introduction • Recommendations for prevention strive to maximize benefits and minimize harms. • Competing factors: US population highly enthusiastic about frequent cancer screening; medical-legal environment rewards vigilance from clinicians. Sawaya GF N Engl J Med 2009 361;26 2503-2505

  7. Introduction (Continued) • Controversies common in determining when to begin, when to end, screening frequency and use of newer screening technologies. • USPSTF: widely recognized as setting the standard for evidence-based recommendations related to prevention. Sawaya GF N Engl J Med 2009 361;26 2503-2505

  8. Introduction (Continued) • Devising recommendations for prevention can be complicated at all steps. • Determining the appropriate balance between benefits and harms is challenging. Sawaya GF N Engl J Med 2009 361;26 2503-2505

  9. What is the US Preventive Services Task Force? Congressionally mandated independent panel of non-Federal experts in prevention and evidence-based medicine 16 primary care providers (e.g., internists, pediatricians, family physicians, gynecologists/obstetricians, nurses and health behavior specialists) http://www.uspreventiveservicestaskforce.org/about.htm

  10. What is the USPSTF Mission? “to evaluate the benefits of individual services based on age, gender, and risk factors for disease; make recommendations about which preventive services should be incorporated routinely into primary medical care and for which populations; and identify a research agenda for clinical preventive care.” www.uspreventiveservicestaskforce.org/about.htm

  11. Who Supports the USPSTF? Administrative, research, technical and dissemination support provided by the Agency for Healthcare Research and Quality (AHRQ) Scientific support from AHRQ-funded Evidence-Based Practice Centers (EPCs) 14 EPCs in the US and Canada EPCs conduct systematic evidence reviews on topics in clinical prevention that serve as the scientific basis for USPSTF recommendations EPC products: evidence reports and technology assessments www.uspreventiveservicestaskforce.org/about.htm

  12. What are US Preventive Services Task Force Activities? Task Force does not consider costs, medical-legal issues or insurance coverage in deliberations Develops recommendations for primary care clinicians and health systems on a broad range of clinical preventive health care services (e.g., screening, counseling, and preventive medications) http://www.uspreventiveservicestaskforce.org/about.htm

  13. What are US Preventive Services Task Force Activities? Recommendations published in the form of “recommendation statements”; opportunity for public comment provided Affordable Care Act (July 2010) singles out positive recommendations by the USPSTF (those deemed an “A” or “B”) for coverage Recommendations graded to convey two major elements: certainty and magnitude of net benefit of the preventive service http://www.uspreventiveservicestaskforce.org/about.htm

  14. USPSTF Grades of Recommendations www.uspreventiveservicestaskforce.org/uspstf/grades.htm

  15. What the Grades Mean: Suggestions for Practice http://www.uspreventiveservicestaskforce.org/uspstf/grades.htm

  16. The USPSTF Steps: Brief and Generic Define key questions and outcomes, including an analytic framework, for each Task Force topic subgroup Define, retrieve and summarize relevant evidence (EPCs) Judge quality of individual studies: good, fair, poor (EPCs) Synthesize and judge the adequacy of the evidence about benefits and harms: convincing, adequate, inadequate (TF topic subgroup) • www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm

  17. The USPSTF Steps: Brief and Generic Determine and judge the magnitude of both benefits and harms: substantial, moderate, small, zero Determine and judge the balance of benefits and harms (net benefit) (TF topic subgroup) Judge the certainty of net benefit: low, moderate, high (TF) Judge the magnitude of net benefit: substantial, moderate, small, zero/negative (TF) Assign a letter grade: A, B, C, D. I Note: Judgment is required at all steps • www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm • .

  18. The USPSTF Steps: Brief and Generic Step 1: Define key questions and outcomes, including an analytic framework, for each Task Force topic subgroup (Note: CEA = carotid endarterectomy) • www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm

  19. The USPSTF Steps: Brief and Generic Step 2: Define, retrieve and summarize relevant evidence (role of EPCs) Step 3: Judge quality of individual studies: good, fair, poor (role of EPCs) Step 4: Synthesize and judge the adequacy of the evidence about benefits and harms: convincing, adequate, inadequate (TF topic subgroup) • www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm

  20. Systematic Reviews by EPCs • A planned, comprehensive, reproducible, exhaustive review of the world’s literature on a given topic • Includes electronic resources (e.g., MEDLINE, EMBASE), experts and review of reference lists • May include unpublished studies (but often does not, so ‘publication bias’ is always a concern) • Always valuable

  21. Meta-Analysis by EPCs • The quantitative component of a systematic literature review that summarizes data from several studies-- • To determine a summary estimate of effect to estimate the likelihood of benefit and harm • To increase statistical power that may be lacking due to too many small studies • To evaluate a potential effect in subgroups • To determine if further placebo-controlled trials would be unethical • Caution must be exercised to determine if studies can be combined

  22. The USPSTF Steps (continued): Brief and Generic Step 5: Determine and judge the magnitude of both benefits and harms: substantial, moderate, small, zero Step 6: Determine and judge the balance of benefits and harms (net benefit) (Task Force topic subgroup) Step 7: Judge the certainty of net benefit: low, moderate, high (Task Force) Step 8: Judge the magnitude of net benefit: substantial, moderate, small, zero/negative (Task Force) Step 9: Assign a letter grade: A, B, C, D, I NOTE: Judgment is required at every step. • www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm • .

  23. Breast Cancer Screening

  24. Returning to the Patient Case • A 40-year-old woman presents to your clinic for a periodic health examination. She is healthy and has no risk factors for any particular diseases. She does not smoke, is sexually active and is not pregnant. • Routine mammography is not recommended by the USPSTF. • She has read about the mammography controversy and wants to know more about the benefits and harms.

  25. Devising Breast Cancer Screening Recommendations: The USPSTF Approach

  26. Analytic Framework: Screening for Breast Cancer 2 major key questions (see next slide) http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanupappfig1.htm

  27. Analytic Framework: Key questions inScreening for Breast Cancer 1 a) Does screening with mammography (film and digital) or MRI decrease breast cancer mortality among women age 40–49 years and ≥70 years? 1 b) Does clinical breast examination screening decrease breast cancer mortality? Alone or with mammography? 1 c) Does breast self-examination practice decrease breast cancer mortality? http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanupappfig1.htm

  28. Analytic Framework: Key questions inScreening for Breast Cancer (Continued) 2 a) What are the harms associated with screening with mammography (film and digital) and MRI? 2 b) What are the harms associated with clinical breast examination ? 2 c) What are the harms associated with breast self-examination? http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanupappfig1.htm

  29. Breast Cancer Screening: Benefits • Decreased breast cancer mortality and total mortality • Decreased morbidity from breast cancer (reduction of late-stage breast cancer) www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanup.htm

  30. Breast Cancer Screening: Harms • Radiation exposure • Pain during procedures • Anxiety, distress, and other psychological responses • False-positive and false-negative mammography results, additional imaging, and biopsies www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanup.htm

  31. Evidence of Benefit: Mammography by Age Group http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanup.htm#tab1

  32. Evidence of Harms: Other Evidence Related to Mammography • Data about harms often obtained from a variety of sources. • For breast cancer screening, data from 600,830 women aged 40+ years undergoing routine mammography screening at Breast Cancer Surveillance Consortium (BCSC) sites obtained • BCSC data intended to represent the experience of a cohort of regularly screened women www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanup.htm

  33. Evidence of Harms: False Positive Testing with Mammography • Estimated risk of false positive testing after 10 mammograms (all ages): 21-49% • Estimated risk of false positive testing after 10 mammograms in women aged 40-49: 56% www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanup.htm

  34. Judging Evidence of Benefit of Mammography • There is convincing evidence that screening with film mammography reduces breast cancer mortality, with a greater absolute reduction for women aged 50 to 74 years than for women aged 40 to 49 years. • The strongest evidence for the greatest benefit is among women aged 60 to 69 years. www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  35. Judging Evidence ofHarm of Mammography There is adequate evidence that the overall harms associated with mammography are moderate for every age group considered. False-positive results are more common for women aged 40 to 49 years, whereas “overdiagnosis” is a greater concern for women in the older age groups. www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  36. Putting it all Together: Balancing Benefits and Harms of Mammography Decision analysis is a method by which the balance of benefits and harms can be judged. USPSTF commissioned a decision analysis to assist in the determination of net benefit. www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  37. Decision Analysis • Estimates the outcomes of different clinical decisions • Estimates both benefits and harms • Breaks down problem into components: treatment options, outcome probabilities with each option (both benefitsandharms) • Uses systematic reviews and meta-analyses • Applies to large, theoretic cohorts of individuals going forward in time (effectiveness)

  38. Putting it all Together: Balancing Benefits and Harms of Mammography Benefits: • Percentage of mortality reduction • Cancer deaths averted per 1000 women • Life years gained • “life-year”: a measure of the quantity of life lived • may be expressed as “life years expected per 1000 people” for an intervention strategy www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanart.htm

  39. Putting it all Together: Balancing Benefits and Harms of Mammography Harms: • False-positive results per 1000 women • Unnecessary biopsies per 1000 women www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanart.htm

  40. Putting it all Together: Balancing Benefits and Harms of Mammography Conclusion (all age groups): Biennial screening produced 70% to 99% of the benefit of annual screening, with a significant reduction in the number of mammograms required and therefore a decreased risk for harms. www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  41. Putting it all Together: Balancing Benefits and Harms of Mammography • Screening between the ages of 50 and 69 years produced a projected 17% (range, 15% to 23%) reduction in mortality (compared with no screening) • Extending the age range produced only minor improvements (additional 3% reduction from starting at age 40 years and 7% from extending to age 79) http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  42. Evidence of Net Benefit of Mammography Estimation of certainty and magnitude of net benefit (benefit minus harm): • For biennial screening mammography in women aged 40 to 49 years, there is moderate certaintythat the net benefit is small. http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  43. Evidence of Net Benefit of Mammography Estimation of certainty and magnitude of net benefit (benefit minus harm): • The USPSTF emphasizes the adverse consequences for most women—who will not develop breast cancer—and therefore use the number needed to screen to save 1 life as its metric. By this metric, the USPSTF concludes that there is moderate evidence that thenet benefit is small for women aged 40 to 49 years. • For biennial screening mammography in women aged 50 to 74 years, there is moderate certainty that the net benefit is moderate. http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  44. Further “The additional benefit gained by starting screening at age 40 years rather than at age 50 years is small, and …. moderate harms from screening remain at any age. This leads to the ‘C’ recommendation. “A ‘C’ grade is a recommendation against routine screening of women aged 40 to 49 years. The Task Force encourages individualized, informed decision making about when to start…” www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  45. Back to the Case: Talking to Patients About Mammography • “The precise age at which the benefits from screening mammography justify the potential harms is a subjective judgment and should take into account patient preferences.” • “Clinicians should inform women about the potential benefits (reduced chance of dying from breast cancer), potential harms (for example, false-positive results, unnecessary biopsies), and limitations of the test that apply to women their age.” http://www.uspreventiveservicestaskforce.org/uspstf09/breastcancer/brcanrs.htm

  46. Summary • Devising recommendations for prevention can be complicated at all steps. • While screening benefits are often cited and widely promulgated, the USPSTF gives equal attention to screening harms. • Determining the appropriate balance between benefits and harms is challenging. • http://www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm

  47. Summary • Different groups may evaluate the same evidence and arrive at different conclusions. • The USPSTF method of devising recommendations involves judgment at all steps but strives for transparency. • http://www.uspreventiveservicestaskforce.org/uspstf07/methods/benefit.htm

  48. Questions and Comments

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