Evidence of influence: how to avoid!
Definition <ul><li>Evidence-based medicine  (EBM) or  scientific medicine  is  </li></ul><ul><ul><li>an attempt  to apply ...
History <ul><li>Testing medical interventions for efficacy has existed for several hundred years.  </li></ul>
History <ul><li>Professor  Archie Cochrane , a Scottish epidemiologist, through his book  Effectiveness and Efficiency: Ra...
Professor  Archie Cochrane   (1909-1988)
Classification <ul><li>Two types of evidence-based medicine have been proposed . </li></ul><ul><ul><li>Evidence-based guid...
Qualification of evidence (USA) <ul><li>Level I:  Evidence obtained from at least one properly designed  randomized contro...
Qualification of evidence (USA) <ul><li>Level II (Cont) </li></ul><ul><ul><li>II-2: Evidence obtained from well-designed  ...
Qualification of evidence(UK) <ul><li>Level A:  consistent  Randomised Controlled Clinical Trial ,  Cohort Study , All or ...
Qualification of evidence(UK) <ul><li>Level C:  Case-series Study or extrapolations from level B studies  </li></ul><ul><l...
Categories of recommendations <ul><li>In guidelines and other publications, recommendation for a clinical service  is clas...
Categories of recommendations  <ul><li>The  U.S. Preventive Services Task Force  uses: </li></ul><ul><li>Level A:   Good  ...
Categories of recommendations <ul><li>Level C:  At  least fair  scientific evidence suggests that there are  benefits  pro...
Categories of recommendations <ul><li>Level I:   Scientific evidence is lacking , of poor quality, or conflicting, such th...
Criticism of evidence-based medicine
Criticism of evidence-based medicine <ul><li>Critics of EBM say lack of evidence and lack of benefit are not the same,  </...
Criticism of evidence-based medicine <ul><li>In some cases, such as in open-heart surgery, conducting randomized controlle...
Criticism of evidence-based medicine <ul><li>The types of trials considered &quot;gold standard&quot; (i.e. randomized dou...
Criticism of evidence-based medicine <ul><li>Evidence-based  guidelines  do not remove the problem of  extrapolation  to d...
Evidence of influence
Evidence of influence   <ul><li>Increasingly, biomedical studies receive funding from  </li></ul><ul><ul><li>commercial fi...
Evidence of influence   <ul><li>Other research studies have suggested that funding is a source of bias; studies sponsored ...
Evidence of influence <ul><li>The question that should be asked, why drug companies would be interested in clinical trials...
How to avoid <ul><li>First , scientists have an  ethical obligation  to submit creditable research results for publication...
How to avoid <ul><li>Researchers should not enter into agreements that interfere with  </li></ul><ul><ul><li>their access ...
How to avoid <ul><li>Authors should describe the role of the study sponsor(s), if any,  </li></ul><ul><ul><li>in study des...
How to avoid <ul><li>Second,  to encourage conducting RCTs, because randomized controlled trials are generally considered ...
How to avoid <ul><li>Properly done, this procedure means that the different groups are comparable at outset, reducing the ...
How to avoid <ul><li>Third:   to conduct a systematic review of RCTs and to do a sensitivity analysis between studies with...
How to avoid <ul><li>Unfortunately, two recent systematic reviews of the impact of financial conflicts on biomedical resea...
How to avoid <ul><li>This  could not  be explained by the reported quality of the methods in research sponsored by industr...
How to avoid <ul><li>That’s why meta-analysis has got the top of the evidence hierarchy </li></ul>
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Evidence of influence

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Evidence of influence

  1. 1. Evidence of influence: how to avoid!
  2. 2. Definition <ul><li>Evidence-based medicine (EBM) or scientific medicine is </li></ul><ul><ul><li>an attempt to apply more uniformly </li></ul></ul><ul><ul><li>the standards of evidence </li></ul></ul><ul><ul><li>gained from the sceintific method </li></ul></ul><ul><ul><li>to certain aspects of medical practice . </li></ul></ul><ul><li>&quot;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 </li></ul>
  3. 3. History <ul><li>Testing medical interventions for efficacy has existed for several hundred years. </li></ul>
  4. 4. History <ul><li>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 </li></ul><ul><li>The term &quot;evidence-based medicine&quot; first appeared in the medical literature in 1992 in a paper by Guyatt et al </li></ul>
  5. 5. Professor Archie Cochrane (1909-1988)
  6. 6. Classification <ul><li>Two types of evidence-based medicine have been proposed . </li></ul><ul><ul><li>Evidence-based guidelines </li></ul></ul><ul><ul><ul><li>Evidence-based guidelines (EBG) is the practice of evidence-based medicine at the organizational or institutional level. </li></ul></ul></ul><ul><ul><li>Evidence-based individual decision making </li></ul></ul><ul><ul><ul><li>Evidence-based individual decision (EBID) making is evidence-based medicine as practiced by the individual health care provider . </li></ul></ul></ul>
  7. 7. Qualification of evidence (USA) <ul><li>Level I: Evidence obtained from at least one properly designed randomized controlled trial . </li></ul><ul><li>Level II </li></ul><ul><ul><li>II-1: Evidence obtained from well-designed controlled trials without randomization . </li></ul></ul>
  8. 8. Qualification of evidence (USA) <ul><li>Level II (Cont) </li></ul><ul><ul><li>II-2: Evidence obtained from well-designed cohort or case-control analytic studies </li></ul></ul><ul><ul><li>II-3: Evidence obtained from multiple time series with or without the intervention. </li></ul></ul><ul><li>Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees. </li></ul>
  9. 9. Qualification of evidence(UK) <ul><li>Level A: consistent Randomised Controlled Clinical Trial , Cohort Study , All or None, Clinical Decision Rule validated in different populations. </li></ul><ul><li>Level B: consistent Retrospective Cohort, Exploratory Cohort, Ecological Study, Outcomes Research, Case-Control Study; or extrapolations from level A studies. </li></ul>
  10. 10. Qualification of evidence(UK) <ul><li>Level C: Case-series Study or extrapolations from level B studies </li></ul><ul><li>Level D: Expert opinion without explicit critical appraisal, or based on physiology, bench research or first principles </li></ul>
  11. 11. Categories of recommendations <ul><li>In guidelines and other publications, recommendation for a clinical service is classified by </li></ul><ul><ul><li>the balance of risk </li></ul></ul><ul><ul><li>versus benefit of the service </li></ul></ul><ul><ul><li>and the level of evidence on which this information is based. </li></ul></ul>
  12. 12. Categories of recommendations <ul><li>The U.S. Preventive Services Task Force uses: </li></ul><ul><li>Level A: Good scientific evidence suggests that the benefits of the clinical service substantially outweighs the potential risks . </li></ul><ul><ul><li>Clinicians should discuss the service with eligible patients. </li></ul></ul><ul><li>Level B: At least fair scientific evidence suggests that the benefits of the clinical service outweighs the potential risks . </li></ul><ul><ul><li>Clinicians should discuss the service with eligible patients. </li></ul></ul>
  13. 13. Categories of recommendations <ul><li>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. </li></ul><ul><ul><li>Clinicians need not offer it unless there are individual considerations. </li></ul></ul><ul><li>Level D: At least fair scientific evidence suggests that the risks of the clinical service outweighs potential benefits . </li></ul><ul><ul><li>Clinicians should not routinely offer the service to asymptomatic patients. </li></ul></ul>
  14. 14. Categories of recommendations <ul><li>Level I: Scientific evidence is lacking , of poor quality, or conflicting, such that the risk versus benefit balance cannot be assessed. </li></ul><ul><ul><li>Clinicians should help patients understand the uncertainty surrounding the clinical service. </li></ul></ul>
  15. 15. Criticism of evidence-based medicine
  16. 16. Criticism of evidence-based medicine <ul><li>Critics of EBM say lack of evidence and lack of benefit are not the same, </li></ul><ul><li>There are a number of reasons why most current medical and surgical practices do not have a strong literature base supporting them. </li></ul>
  17. 17. Criticism of evidence-based medicine <ul><li>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. </li></ul><ul><li>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 </li></ul><ul><li>The quality of studies performed varies , making it difficult to generalize about the results. </li></ul>
  18. 18. Criticism of evidence-based medicine <ul><li>The types of trials considered &quot;gold standard&quot; (i.e. randomized double-blind placebo-controlled trials) may be expensive , so that funding sources play a role in what gets investigated. </li></ul><ul><li>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 ) </li></ul>
  19. 19. Criticism of evidence-based medicine <ul><li>Evidence-based guidelines do not remove the problem of extrapolation to different populations or longer timeframes. </li></ul><ul><li>Furthermore, skepticism about results may always be extended to areas not explicitly covered: for example a drug may influence a &quot;secondary endpoint&quot; 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. </li></ul>
  20. 20. Evidence of influence
  21. 21. Evidence of influence <ul><li>Increasingly, biomedical studies receive funding from </li></ul><ul><ul><li>commercial firms </li></ul></ul><ul><ul><li>private foundations </li></ul></ul><ul><ul><li>and government. </li></ul></ul><ul><li>The conditions of this funding have the potential to bias. </li></ul><ul><li>Bias comes about when the findings of research appear to differ in some systematic way from the true result </li></ul>
  22. 22. Evidence of influence <ul><li>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 </li></ul>
  23. 23. Evidence of influence <ul><li>The question that should be asked, why drug companies would be interested in clinical trials!! </li></ul><ul><li>It is estimated that the average cost of bringing a new drug to market in the United States is about $500 million </li></ul><ul><li>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. </li></ul>
  24. 24. How to avoid <ul><li>First , scientists have an ethical obligation to submit creditable research results for publication . </li></ul>
  25. 25. How to avoid <ul><li>Researchers should not enter into agreements that interfere with </li></ul><ul><ul><li>their access to the data </li></ul></ul><ul><ul><li>or their ability to analyze the data independently, </li></ul></ul><ul><ul><li>to prepare manuscripts, </li></ul></ul><ul><ul><li>and to publish them. </li></ul></ul>
  26. 26. How to avoid <ul><li>Authors should describe the role of the study sponsor(s), if any, </li></ul><ul><ul><li>in study design; </li></ul></ul><ul><ul><li>in the collection, analysis and interpretation of data; </li></ul></ul><ul><ul><li>in the writing of the report; </li></ul></ul><ul><ul><li>and in the decision to submit the report for publication. (http://www.icmje.org/sponsor.htm) </li></ul></ul>
  27. 27. How to avoid <ul><li>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. </li></ul><ul><li>Randomization involves the assignment of participants in the trial to different treatment groups by the play of chance. </li></ul>
  28. 28. How to avoid <ul><li>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. </li></ul><ul><li>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. </li></ul>
  29. 29. How to avoid <ul><li>Third: to conduct a systematic review of RCTs and to do a sensitivity analysis between studies with and without funding. </li></ul>
  30. 30. How to avoid <ul><li>Unfortunately, two recent systematic reviews of the impact of financial conflicts on biomedical research found that </li></ul><ul><ul><li>studies financed by industry, although as rigorous as other studies, always found outcomes favorable to the sponsoring company </li></ul></ul>
  31. 31. How to avoid <ul><li>This could not be explained by the reported quality of the methods in research sponsored by industry. </li></ul><ul><li>The result may be due to </li></ul><ul><ul><li>inappropriate comparators </li></ul></ul><ul><ul><li>or to publication bias. </li></ul></ul>
  32. 32. How to avoid <ul><li>That’s why meta-analysis has got the top of the evidence hierarchy </li></ul>
  33. 33. Thank You

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