What is Evidence Based Medicine?

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Certainly, it makes sense to choose clinically proven medications. We hear it more and more often but what does Evidence-Based Medicine really mean? It is a relatively new term, having only been around since the early 1990’s, for the scientific classification of evidence.When we use the term “evidence-based” we are saying that this particular treatment has scientific studies that indicate the treatment is effective to some degree. That is why at Moontides, we choose to use “Practitioner Only Products” whenever possible.

There are many types of scientific studies and each has a different way in which the evidence is collected. This is why some studies are deemed of greater scientific importance than others. In particular, ‘double-blind randomised control studies’ are generally accepted as the most advantageous due to the comparative evidence that can be drawn and the inability for researchers to bias the data collected. The type of study used will depend on the factor being studied. For example, in Australia we have quite strict ethic controls about the types of studies that can be carried out and this can result in limited findings.

The most commonly used forms of research for gaining evidence.

  • Traditional / Historical – Traditional evidence is historical information about the efficacy of a treatment that has been passed down through generations. Traditional medicine, practiced around the world, forms the medical system that has been replaced by today’s evidence based model.Clinical Trials- Clinical trials carried out on people are generally designed to test the effectiveness of a drug. However, it’s becoming more popular for some types of therapies to also be tested.

There are several types of clinical trials, as seen below.

A study that uses a combination of these types of trials is generally given greater credence. Eg. A double-blind randomised placebo controlled trial will be considered of greater value than a randomised, control trial.

  • Randomised Controlled Trials – Participants in randomised control trials are divided into two or more groups (usually using a computer generated program). One group will receive the treatment or therapy being tested. The second group will receive a placebo or the standard treatment for the condition being studied.
  • Double Blind Trials – In this type of trial, neither the subjects being studied nor the researcher knows who is being treated and who is receiving a placebo.
  • Placebo Controlled Trials – In a placebo-controlled trial, some of the subjects will receive a placebo, while others will receive the actual drug or treatment being studied.
  • Cohort Studies – A cohort study is where a group of people are followed over a long period of time. An example of this would be a study that compared smokers versus non-smokers and the incidence of lung cancer.
  • In-vitro – In-vitro is Latin for ‘in-glass’ and refers to studies that are carried out in test tubes. That is, they are determining the effects of a drug on a particular group or type of cells. Positive in-vitro results will often lead to in-vivo tests being carried out.
  • In-vivo – In vivo refers to research that is done on a whole body system. Usually this means animal tests, followed by human studies.
  • Reviews – This is a peer review of a particular study.
  • Meta-analysis – This is a peer review of all available literature to determine whether or not the overall results indicate a positive outcome in light of the questions posed.

Problems with evidence based medicine

One of the biggest problems with evidence-based medicine is the fact that few negative trials are ever published, meaning that if the researchers did not achieve the result they were hoping for, then that information is scrapped. The trial may then be conducted again with a different set of conditions, achieving a positive result that is then published.

In the world of evidence based medicine, randomised double blind controlled trials are deemed superior studies. However, they can also pose ethical problems. For example, we cannot do a randomised, double blind controlled study on heart transplants.

Randomised double blind controlled trials can be very expensive and this can limit the choices of subjects studied. Therefore, subjects to be studied will be heavily influenced by the funding available. The two main groups who fund studies are a) the government, mostly for the purpose of preventative medicine that will aid a large sector of the public and b) pharmaceutical companies whose studies are aimed at determining the effectiveness of a particular drug for a particular condition.

It is important to note that certain groups in society have been under-researched. In particular, women, racial minorities and children. Much of the medical research behiind today’s medicne was trialled for men.The quality of a study is dependent on the measures of control and/or manipulation exhibited by the researchers. Therefore, the results of a study can be entirely dependent on the work ethics of the individual researcher.

Add to that, some medical journals have a bias towards particular types of research, companies or therapies. This means that only the research fitting the views of the publishers will ever make it to publication.