Statistical knowledge and clinical knowledge. J. Nummenmaa M.D. Ph.D. Knowledge in Medicine -Questions in Medical Epistemology. Evidence-Based Medicine (EBM). Ensure availability of reliable research results for clinicians How effective treatment? Research done on patients
Statistical knowledge and clinical knowledge
Knowledge in Medicine -Questions in Medical Epistemology
Level A: Consistent Randomised Controlled Clinical Trial, cohort study, all or none (see note below), 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.
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.
IS TREATMENT X MORE EFFECTIVE THAN Y IN THE TREATMENT OF DISEASE Z?
N PATIENTS WITH Z
HALF TREATED WITH Y
HALF TREATED WITH X
NUMBER OF END –POINTS IN DIFFERENT GROUPS
SELECTION OF END-POINTS
HOW TO CHOOSE WHAT TREATMENTS ARE COMPARED?
PROBLEMS ON PATIENT SELECTION
PROBLEMS OF DIAGNOSTIC CRITERIA
Statistical significance: p=0.036
Out of onehundredpatients:
-> 97 remainhealthy
-> ARR 1% -> NNT= 100
Recommendations based on same evidence: 50% / 50%
Lack of knowledge
Ethics & values