EBM Exam I

Card Set Information

EBM Exam I
2012-01-31 11:31:37
Trial Design

Trial Design
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  1. Factors determining study design
    • ability to answer primary research question
    • potential new treatment
    • probability of risk to participants
    • probability of participants likely to benefit
    • size & accessibility of studied population
    • how data is used
  2. investigators will take the primary research question and develop
    • a hypothesis to test
    • very important when trying to evaluate the study
  3. observational studies are good for
    discovering things that need to be investigated further
  4. interventional studies are good for
    investigating the effect of a particular change
  5. Prospective study characteristics
    • forward in time
    • gather data on events as they happen
    • creating chart
    • interventional trials
  6. retrospective trial characteristics
    • backward in time
    • gather data from historical documentation
    • looking at chart
    • subject to recall bias
  7. observational trials may be
    pro or retrospective
  8. uncontrolled trial characteristics
    • results of one group's experince
    • can't determine cause and effect
    • interventional or observational
    • no "control group"
  9. Controlled trial characteristics
    • One group's results compared to results of group not experiencing event
    • two or more groups
    • interventional or observational
  10. when determining efficacy, the control is
  11. when determining efectiveness/efficaciousness the control is
  12. Dose comparison trial controls are
    two different doses along with placebo group
  13. Randomized trial characteristics
    • must have 2 or more groups
    • individuals randomly assigned
    • may be possible in retrospective studies
  14. Non-randomized trial characterizations
    • may be 1 or more groups
    • individuals assigned to group based on certain traits or by choice of investigator
    • groups may not be similar
  15. when factors are known that are highly likely to affect the results or be predictive of disease progression
    • stratification
    • ie: try to put the same number of smokers in each group
  16. Parallel trial characteristics
    • two or more groups have different experiences at the same time
    • most common
  17. cross-over trial characteristics
    • one group having two or more experiences at different times
    • each individual serves as his own control
    • "paired data"
    • smaller groups required
  18. advantages of Study diagrams
    • visual aid
    • understand complex study designs
    • identify potential problems
  19. Single Blinded trial characteristics
    either pt or investigator knows assignment
  20. double blinded trial characteristics
    • neither patient nor investigator knows assignments
    • more objective observation of results
  21. Un-Blinded trial characteristics
    • investigator and pt know what group pt is in
    • outcomes may be reported differently
  22. Inclusion criteria
    • "to be in the study, pt must..."
    • aids in addressing hypothesis
    • "fine-tune" a diagnosis
  23. Exclusion criteria
    • "to be in the study, a pt must not..."
    • reduces risk and complications for pt
  24. single study site
    • smaller numbers of pt
    • easy communication
    • easy data collection
  25. multiple study sites
    • large number of pt
    • challenging to coordinate research efforts
  26. Type I clinical study
    • prospective
    • interventional
    • controlled
    • statistical power
  27. Type II clinical study
    • prospective
    • interventional
    • controlled
    • no power
  28. Type III clinical study
    • prospective
    • observational
    • comparison groups
    • cohort studies
  29. Type IV clinical study
    • retrospective
    • observational
    • comparison groups
    • case control study
  30. Type V clinical studies
    • prospective
    • interventional or observational
    • uncontrolled
  31. Descriptive study designs
    • document and communicate experience
    • share observations & unusual events
    • case report or series
  32. Explanatory study design
    • examin cause
    • efficacy/etiology using method of comparisons
    • clinical trials, case controls, cohorts, cross-sectional
  33. Examples of interventional/experimental studies (clinical trials)
    • superiority
    • non-inferiority
    • equivalency
  34. Observational studies seek
    • causes
    • etiologies
    • predictors
  35. examples of observational studies
    • cohort
    • case control
    • cross-sectional
  36. Cohort study
    • prospective or retrospective
    • observational
  37. Case Control Study
    • retrospective
    • observational
    • match a person with an outcome of interest to a similar person without and look for differences in variables
  38. cross sectional study
    • slice in time
    • observational
    • blend of cohort and case study
    • prevalence study