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Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
Evidence of influence
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Evidence of influence

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Transcript

  • 1. Evidence of influence: how to avoid!
  • 2. Definition
    • Evidence-based medicine (EBM) or scientific medicine is
      • an attempt to apply more uniformly
      • the standards of evidence
      • gained from the sceintific method
      • to certain aspects of medical practice .
    • "Evidence-based medicine is the conscientious , explicit and judicious use of current best evidence in making decisions about the care of individual patients.” According to the Centre for Evidence-Based Medicine
  • 3. History
    • Testing medical interventions for efficacy has existed for several hundred years.
  • 4. History
    • Professor Archie Cochrane , a Scottish epidemiologist, through his book Effectiveness and Efficiency: Random Reflections on Health Services (1972) and subsequent advocacy, caused increasing acceptance of the concepts behind evidence-based
    • The term "evidence-based medicine" first appeared in the medical literature in 1992 in a paper by Guyatt et al
  • 5. Professor Archie Cochrane (1909-1988)
  • 6. Classification
    • Two types of evidence-based medicine have been proposed .
      • Evidence-based guidelines
        • Evidence-based guidelines (EBG) is the practice of evidence-based medicine at the organizational or institutional level.
      • Evidence-based individual decision making
        • Evidence-based individual decision (EBID) making is evidence-based medicine as practiced by the individual health care provider .
  • 7. Qualification of evidence (USA)
    • Level I: Evidence obtained from at least one properly designed randomized controlled trial .
    • Level II
      • II-1: Evidence obtained from well-designed controlled trials without randomization .
  • 8. Qualification of evidence (USA)
    • Level II (Cont)
      • II-2: Evidence obtained from well-designed cohort or case-control analytic studies
      • II-3: Evidence obtained from multiple time series with or without the intervention.
    • Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
  • 9. Qualification of evidence(UK)
    • Level A: consistent Randomised Controlled Clinical Trial , Cohort Study , All or None, Clinical Decision Rule validated in different populations.
    • Level B: consistent Retrospective Cohort, Exploratory Cohort, Ecological Study, Outcomes Research, Case-Control Study; or extrapolations from level A studies.
  • 10. Qualification of evidence(UK)
    • Level C: Case-series Study or extrapolations from level B studies
    • Level D: Expert opinion without explicit critical appraisal, or based on physiology, bench research or first principles
  • 11. Categories of recommendations
    • In guidelines and other publications, recommendation for a clinical service is classified by
      • the balance of risk
      • versus benefit of the service
      • and the level of evidence on which this information is based.
  • 12. Categories of recommendations
    • The U.S. Preventive Services Task Force uses:
    • Level A: Good scientific evidence suggests that the benefits of the clinical service substantially outweighs the potential risks .
      • Clinicians should discuss the service with eligible patients.
    • Level B: At least fair scientific evidence suggests that the benefits of the clinical service outweighs the potential risks .
      • Clinicians should discuss the service with eligible patients.
  • 13. Categories of recommendations
    • Level C: At least fair scientific evidence suggests that there are benefits provided by the clinical service, but the balance between benefits and risks are too close for making general recommendations.
      • Clinicians need not offer it unless there are individual considerations.
    • Level D: At least fair scientific evidence suggests that the risks of the clinical service outweighs potential benefits .
      • Clinicians should not routinely offer the service to asymptomatic patients.
  • 14. Categories of recommendations
    • Level I: Scientific evidence is lacking , of poor quality, or conflicting, such that the risk versus benefit balance cannot be assessed.
      • Clinicians should help patients understand the uncertainty surrounding the clinical service.
  • 15. Criticism of evidence-based medicine
  • 16. Criticism of evidence-based medicine
    • Critics of EBM say lack of evidence and lack of benefit are not the same,
    • There are a number of reasons why most current medical and surgical practices do not have a strong literature base supporting them.
  • 17. Criticism of evidence-based medicine
    • In some cases, such as in open-heart surgery, conducting randomized controlled trials would be unethica l, although observational studies may address these problems to some degree.
    • Certain groups have been historically under-researched (racial minorities and people with many co-morbid diseases), and thus the literature is sparse in areas that do not allow for generalizing
    • The quality of studies performed varies , making it difficult to generalize about the results.
  • 18. Criticism of evidence-based medicine
    • The types of trials considered "gold standard" (i.e. randomized double-blind placebo-controlled trials) may be expensive , so that funding sources play a role in what gets investigated.
    • The studies that are published in medical journals may not be representative of all the studies that are completed on a given topic (published and unpublished) or may be misleading due to conflicts of interest (i.e. publication bias )
  • 19. Criticism of evidence-based medicine
    • Evidence-based guidelines do not remove the problem of extrapolation to different populations or longer timeframes.
    • Furthermore, skepticism about results may always be extended to areas not explicitly covered: for example a drug may influence a "secondary endpoint" such as test result (blood pressure, glucose, or cholesterol levels) without having the power to show that it decreases overall mortality or morbidity in a population.
  • 20. Evidence of influence
  • 21. Evidence of influence
    • Increasingly, biomedical studies receive funding from
      • commercial firms
      • private foundations
      • and government.
    • The conditions of this funding have the potential to bias.
    • Bias comes about when the findings of research appear to differ in some systematic way from the true result
  • 22. Evidence of influence
    • Other research studies have suggested that funding is a source of bias; studies sponsored by drug companies seem to more often favor the sponsor's drug than trials not sponsored by drug companies
  • 23. Evidence of influence
    • The question that should be asked, why drug companies would be interested in clinical trials!!
    • It is estimated that the average cost of bringing a new drug to market in the United States is about $500 million
    • The pharmaceutical industry has recognized the need to control costs and has discovered that private nonacademic research groups--that is, contract research organizations (CROs)--can do the job for less money and with fewer hassles than academic investigators.
  • 24. How to avoid
    • First , scientists have an ethical obligation to submit creditable research results for publication .
  • 25. How to avoid
    • Researchers should not enter into agreements that interfere with
      • their access to the data
      • or their ability to analyze the data independently,
      • to prepare manuscripts,
      • and to publish them.
  • 26. How to avoid
    • Authors should describe the role of the study sponsor(s), if any,
      • in study design;
      • in the collection, analysis and interpretation of data;
      • in the writing of the report;
      • and in the decision to submit the report for publication. (http://www.icmje.org/sponsor.htm)
  • 27. How to avoid
    • Second, to encourage conducting RCTs, because randomized controlled trials are generally considered to be the most reliable type of experimental study for evaluating the effectiveness of different treatments.
    • Randomization involves the assignment of participants in the trial to different treatment groups by the play of chance.
  • 28. How to avoid
    • Properly done, this procedure means that the different groups are comparable at outset, reducing the chance that outside factors could be responsible for treatment effects seen in the trial.
    • When done properly, randomization also ensures that the clinicians recruiting participants into the trial cannot know the treatment group to which a patient will end up being assigned.
  • 29. How to avoid
    • Third: to conduct a systematic review of RCTs and to do a sensitivity analysis between studies with and without funding.
  • 30. How to avoid
    • Unfortunately, two recent systematic reviews of the impact of financial conflicts on biomedical research found that
      • studies financed by industry, although as rigorous as other studies, always found outcomes favorable to the sponsoring company
  • 31. How to avoid
    • This could not be explained by the reported quality of the methods in research sponsored by industry.
    • The result may be due to
      • inappropriate comparators
      • or to publication bias.
  • 32. How to avoid
    • That’s why meta-analysis has got the top of the evidence hierarchy
  • 33. Thank You

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