Brief introduction to different types of studies (Pyramid of Evidence)

2,561 views

Published on

Published in: Health & Medicine, Education
0 Comments
5 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,561
On SlideShare
0
From Embeds
0
Number of Embeds
6
Actions
Shares
0
Downloads
0
Comments
0
Likes
5
Embeds 0
No embeds

No notes for slide
  • An observational studyCompare two groups: CASES: a group with the outcome of interest (e.g., non-healed fractures)CONTROLS: a similar group without the outcome of interest (e.g., healed fractures)Determine how many patients within each group have the risk factor (e.g., smoking Shisha)
  • An observational studyYou follow a group of people with certain risk factors and another group without these risk factorsYou follow them for a period of time and look for the outcome of interest
  • Brief introduction to different types of studies (Pyramid of Evidence)

    1. 1. Finding the Answer for Your PICO Question?<br />SohailBajammal<br />October 13, 2011<br />
    2. 2. Steps of Evidence-Based Dentistry<br />✔<br />
    3. 3. Steps of Evidence-Based Dentistry<br />✔<br /><ul><li>Before we go into the “Acquire” and searching, we need to know “what” we are looking for?
    4. 4. Then “where” & “how” to look for it.</li></li></ul><li>What is your PICO?<br />The category of your question will determine what type of study you would expect to find<br />Categories:<br />Therapy (Treatment)<br />Diagnosis<br />Prognosis<br />Harm/Causation<br />Prevention<br />Cost (Economic)<br />Qualitative<br />
    5. 5. Most of your questions<br />Which is better to treat, drug A or drug B?<br />Which is better to treat, oral or IV?<br />Which is better to treat, chemo or radio?<br />
    6. 6. Class Activity<br />10 minutes<br />A group of 5<br />You are a group of researchers. <br />You want to know which is better drug A or drug B in treating patients with hospital-acquired pneumonia in terms of hospital stay<br />How would you do that?<br />Suggest a research design plan<br />
    7. 7. Pyramid of Evidence<br />http://servers.medlib.hscbklyn.edu/ebm/2100.htm<br />
    8. 8. Case Report<br />A descriptive study of one patient<br />Detailed profile of a “rare” presentation or treatment<br />Helpful in developing hypothesis to be tested later using analytic study<br />
    9. 9. Case Series<br />A descriptive study of multiple patients<br />“Rare” phenomenon occurring multiple times<br />Detailed profile of patients’ presentation and outcome<br />Helpful in developing hypothesis<br />
    10. 10. Disadvantages ofCase Report & Case Series<br />Retrospective (looking back in time)<br />Selection bias<br />Recall bias<br />Small sample size<br />That’s why at the bottom of the pyramid<br />
    11. 11. Case-Control Studies(for risk factors)<br />Cases<br />(e.g., Lung Cancer)<br />Shisha Smokers<br />GO BACK IN TIME<br />NOT Shisha Smokers<br />Ask patients<br />Read files<br />Control<br />(e.g., Lung Cancer)<br />Shisha Smokers<br />GO BACK IN TIME<br />NOT Shisha Smokers<br />
    12. 12. Problems with Case-Control Studies<br />Looking back in time (retrospective)<br />Recall bias<br />Measurement bias<br />You may miss important risk factors<br />
    13. 13. Cohort Study<br />Cohort: Roman word for “a group of soldiers that marched into battle together”<br />A group of people followed up with time to see whether an outcome of interest develops<br />Prospective or Retrospective<br />
    14. 14. Prospective Cohort<br />Shisha Smokers<br />Lung Cancer<br />F/U<br />No Lung Cancer<br />NOT Shisha Smokers<br />Lung Cancer<br />F/U<br />No Lung Cancer<br />
    15. 15. Cohort Study<br />Prospective or Retrospective<br />Drawbacks:<br />Large number of patients<br />Follow them up for long time<br />
    16. 16. Randomized Controlled Trial (RCT)<br />Drug A<br />F/U<br />Outcomes<br />Patients with MI<br />RANDOM<br />Drug B<br />F/U<br />Outcomes<br />
    17. 17. Why RCT is the highest level of evidence?<br />Randomization: balance known and unknown prognostic factors<br />Blinding:<br />Patients<br />Researchers<br />Outcome assessors<br />Aim for complete follow-up<br />
    18. 18. Primary Sources<br />Case report<br />Case series<br />Case-control<br />Cohort<br />Randomized controlled trial<br />
    19. 19. Not all studies are good quality<br />After you asked the PICO question<br />You need to find the information (ACQUIRE)<br />Then, you need to “APPRAISE” the quality of each relevant study you find<br />
    20. 20. Where to search for evidence?<br />
    21. 21. Searching for evidence<br />Case report, Case series, Case-Control, Cohort, Randomized Trial<br />DiCenso A, Bayley L, Haynes RB. Accessing preappraised evidence: fine-tuning the 5S model into a 6S model. ACP Journal Club, 2009<br />
    22. 22. Systematic Review<br />Ask a research question (PICO)<br />Set up the studies inclusion & exclusion criteria<br />Literature search:<br />Systematically & thoroughly <br />Keywords & MeSH terms<br />Multiple databases & multiple sources<br />Select the studies & assess their quality<br />Summarize the findings<br />Done in a pair<br />
    23. 23. Meta-analysis<br />All the previous steps<br />Statistical pooling of the results of all studies<br />
    24. 24. Searching for evidence<br />Secondary<br />Primary<br />Case report, Case series, Case-Control, Cohort, Randomized Trial<br />DiCenso A, Bayley L, Haynes RB. Accessing preappraised evidence: fine-tuning the 5S model into a 6S model. ACP Journal Club, 2009<br />
    25. 25. The Usefulness Equation<br />Usefulness = Relevance x Validity<br />of any source Work<br />Shaughnessy AF, Slawson DC, Bennett JH. Becoming an Information Master: A Guidebook to the Medical Information Jungle. The Journal of Family Practice 1994;39(5):489-99.<br />
    26. 26. Relevance: Type of Evidence<br />POE: Patient-oriented evidence <br />mortality, morbidity, quality of life<br />Live longer and/or better<br />DOE: Disease-oriented evidence<br />pathophysiology, pharmacology, etiology<br />Shaughnessy AF, Slawson DC, Bennett JH. Becoming an Information Master: A Guidebook to the Medical Information Jungle. The Journal of Family Practice 1994;39(5):489-99.<br />
    27. 27. Validity<br />The hard part of Information Mastery<br />Technique: EBM working group <br />Guyatt G, Rennie D, ed. Users’ guides to the medical literature. A manual for evidence-based clinical practice. Chicago: AMA, 2002. <br />Did the researchers find what they think they found?<br />Do the results apply to your patients?<br />Self vs delegation- Take responsibility<br />
    28. 28. Work<br />Not all information sources are created equal<br />Two type of information sources<br />“Just-in-case” sources: high work<br />“Just-in-time” sources: low work<br />
    29. 29. Street Smart!<br />
    30. 30. Terms We Talked about Today<br />POE versus DOE<br />Primary Sources versus Secondary Sources<br />Primary:<br />Case report, Case series, Case-Control, Cohort Study, Randomized controlled trial<br />Secondary:<br />Systematic reviews, Synopses, Summary, Systems<br />

    ×