Primer on evidence-based medicine Flashcards
Examination of the evidence from clinical research to justify the diagnosis, prognosis, and treatment of patient
definition of evidence-based medicine (EBM)
What is the new school of thought on EBM?
Observations can be biased
- need a systematic scientific approach to analyze the observations
Meta-analysis Systematic review Randomized controlled trial Cohort studies Case-control studies Case series/ case reports Animal research/ laboratory studies/ cadaveric studies
Levels of evidence (best is on top)
1) Ask - frame the research question (PICOT)
2) Acquire the evidence
3) Appraise and apply the evidence
Steps to analyze literature
PICOT
a way to craft your question in a way that is focused and clinically answerable
P in PICOT
P - patient
- who or what are you studying?
I in PICOT
I - intervention
- what is the treatment or therapy?
C in PICOT
C - comparison
- what are you measuring?
O in PICOT
O - outcomes
- what do you want to measure or prove?
T in PICOT
T - type of study
- do you want to study about therapy, diagnosis, prognosis, etc?
Best kind of research to use
- Always try to find a meta-analysis, systematic review, or randomized controlled trial
- studies that have a treatment and untreated (control) group
Things to consider when looking for literature
Is the study randomized? Was the follow-up complete? Were both groups treated equally? How many people were involved in the study (>100 is optimal, less can be okay)? How many patient loss was there?
Intention to treat
How many patients do I need to treat before I see a benefit?
ex. need to treat 11 patients before one gets better
these studies are more common in surgical specilties
prognostic or case-control study
refers to the possible outcomes of a disease and the frequency with which they can be expected to occur
prognosis
- can predict any outcome, whether good or bad
- do not necessarily cause the outcomes, just be associated with them long enough to predict their development
prognostic factors
patient characteristics associated with development of a disease or condition (ie older women are at increased risk for breast cancer)
risk factors
patient characteristics that help predict whether the patient already with a disease or condition will recover or relapse
prognostic factors (note that it is different than risk factors)
risk for bias, limits its strength as an investigative tool and that is why it’s a level 3 study
retrospective data (memory or charts)
2 or more supporting RCT’s in humans, meta-analysis of RCT’s, or Cochrane Systematic Review of RCT’s
level A (1) - best
1 or more supporting controlled trials in humans or 2 or more trials in an animal model
level B (2)
1 supporting controlled trial, at least 2 supporting case series that were descriptive studies in humans, or expert opinion
level C (3)
1) Was there a representative patient sample at a well-defined point in the course of disease?
2) Was the follow-up sufficiently long and complete?
3) Were objective outcome criteria applied in a “blind” fashion?
is the prognostic (case-control) study valid
summary of medical literature
meta-analysis or systematic review
- both are overviews
1) Did the review address a clearly focused question?
2) Were the criteria used to select articles for inclusion appropriate and reproducible?
3) Were the studies of high quality?
4) Was the search detailed and exhaustive? Were contacts made with authors when questions arose?
questions to ask for meta-analysis or systematic review
