Evidence-Based Medicine

The definition of “evidence-based medicine” is, in many respects, still being formulated by national health services and the international medical community.  We have chosen to utilize the definitions and standards set by the Centre for Evidence Based Medicine at Oxford University.  Accordingly, our definition of Evidence-Based  Medicine is “the conscientious, explicit and judicious use of current best evidence in arriving at conclusions.”

Conclusions in true evidence-based medicine are always formulated on the basis of the best available evidence, not clinical or so-called “expert” opinion.  The purpose of evidence based-medicine is not to conduct research in  order to find a study or analysis that supports a preconceived or desired opinion; but rather, to formulate medical conclusions based on analysis of the best available external evidence. 

Only absent valid external evidence should opinion be relied upon. 

Evidence-based medicine assesses different types of    clinical evidence and ranks them according to the strength of their freedom from various biases. These biases range from mathematical and statistical study   design flaws to overt biases, such as financial or academic interests in outcomes. The best evidence is provided by systematic review of randomized, double-blind trials involving a  homogeneous patient population and medical condition. In contrast, patient testimonials, case reports, or “expert” opinion has limited value in evidence based medicine.

We have adopted a modified version of the United Kingdom’s National Health Service combined with the US Preventive Services task force categorization for studies. They are labeled A, B, C, and D.  Different types of research are required to assess diagnostic accuracy  or prognosis, and hence different "levels" are required. This system utilizes  levels of evidence according to the study designs combined with critical appraisal of prevention, diagnosis, prognosis, therapy, and harm (when such appraisal is mathematically possible).

Level A

  Best Medical Evidence
Consistent , randomized, controlled clinical trials, cohort studies, validated in different populations.

 

 

Level C

Case series studies  or extrapolations from level B studies. Also, evidence obtained from multiple time series with or without  intervention. Dramatic results in uncontrolled trials might also be regarded as this level of evidence.

 

Level B

  Non-randomized, but otherwise well-designed trials, consistent retrospective and/or exploratory cohort studies.   Outcomes Research, case-controlled studies,  or extrapolations from level A studies.

 

 

Level D

  Lowest Level of Medical Evidence
Expert opinion without critical appraisal, or based on bench research, single case reports., patient testimonials or examiner expertise.

 

We make every effort to limit your use of medical evidence to those studies which include broad populations; provide double-blind standards; and are conducted by parties without financial, clinical or academic ties to the study participants and/or procedures, medications or devices under review.