Evidence-based medicine

The history of evidence-based medicine

The history of evidence-based medicine was influenced by two lines of development. On the one hand, it has always been about using scientific tools to find reliable answers to medical questions. But it also concerns providing patients with information about the advantages and disadvantages of medical options so that they can actively make their own decision, perhaps with the help of others.

In previous centuries there have been cases of doctors testing a treatment on one group of patients while using a control group of people who were not given the treatment. In 1753 the Scottish naval surgeon James Lind published the results of his experiment on treating scurvy with lemons and oranges. To test his theory, he divided sailors who were sick with scurvy into groups, making sure that they all had the same living conditions and a similar stage of illness. The groups were then given six different treatments popular at the time, including treatment with fresh fruits.

His study proved what seems obvious to us nowadays: Citrus fruits and other foods that contain vitamin C can heal scurvy. But it still took decades for this knowledge to become universally accepted amongst sailors. 

Video: Cartoon about clinical studies, © ecranproject.euVideo: Cartoon about clinical studies, © ecranproject.eu

How the effects of chance can help to make a comparison

The thing that makes James Lind's experiment remarkable is the idea of a fair comparison. Ensuring that the patient groups are truly comparable prevents one-sided, biased conclusions and allows for reliable results. This underlying idea has been a constant throughout centuries of good research: As early as 1932, the German physician Paul Martini described the fundamental elements of fair studies on medications in his "Methodology of Therapeutic Investigation."

In the late 1940s, groups of researchers in Europe and the U.S. introduced another important basic principle called randomization. “Randomized” means that volunteers are divided into groups by chance, like in a lottery. One of the groups is the treatment group. Participants in this group receive the treatment that is being tested. The other group of participants is called the control group or comparison group. They receive no treatment or a different treatment. The experiences and health events of the participants in each group are recorded so that the resulting data from the groups can be compared. This makes it possible to see what effects the treatment actually has.

The first modern study of a medicine began in England in 1948 when a drug was tested for the treatment of tuberculosis. This study was the first to offer a detailed description of what the researchers did to ensure that the principles of a fair comparison were met. Other large randomized controlled trials followed, including a study conducted in 1954 showing how preterm babies could go blind if they received too much oxygen as part of treatment. Another randomized study was published a few months later, proving that the polio vaccine was effective.

During the 1960s, the method of randomly assigning some participants to comparison groups became the internationally accepted standard for all studies testing the effectiveness and safety of pharmaceuticals and other treatments. Soon afterwards the practice of submitting these studies to health authorities in order to gain official approval for medications was established.

Evidence-based medicine: Definition

The modern idea of evidence-based medicine has been outlined in various publications by American and Canadian researchers and doctors since the 1980s. They had seen that medical decisions made in clinical practice were too often dependent on the habits of individual senior physicians or the marketing efforts of pharmaceutical companies. They disagreed with this approach, instead promoting the idea of medical treatment recommendations that are  based on good arguments and the latest scientific knowledge. Gordon Guyatt from McMaster University in Canada coined the term "evidence-based medicine" in 1990.

The Canadian researcher David Sackett then co-authored the article "Evidence based medicine: What it is and what it isn’t" in 1996 with colleagues. In the article, evidence-based medicine is defined as "the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients." A more recent definition describes EBM as health care in which treatment decisions are based on the best available knowledge from clinical research, the experience of the doctor and the individual preferences and expectations of the patient.

Cochrane Collaboration and Cochrane Library

In 1993 researchers from various countries collaborated to produce systematic reviews together. These reviews are summaries of the results of all the important studies on a specific medical issue. They named their network the "Cochrane Collaboration" in honor of the British epidemiologist Archie Cochrane. Cochrane's book "Effectiveness and Efficiency: Random Reflections on Health Services" was published in 1972 and is now one of the cornerstones of evidence-based medicine. His publications played a major role in the increasing acceptance of randomized controlled trials as standard practice.

In 1989 the textbook "Effective care in pregnancy and childbirth" by the British doctor and researcher Iain Chalmers came out. Its conclusions and recommendations are based on systematic reviews and clinical trial registries. It is considered to be the first evidence-based textbook on treatment, and a precursor to the Cochrane Library – an electronic library of systematic reviews published since 1996.

Evidence-based medicine in clinical practice

Since the 1990s, doctors have faced the challenge of having access to a flood of the latest research results readily available on the internet, but not having enough time or specialist knowledge to fully analyze and interpret the studies on their own. This makes networks like the Cochrane Collaboration, which provide reliable summaries of the studies, ever more important. They enable doctors to get an overview of the available knowledge and apply it. There are now also evidence-based guidelines that offer recommendations for the treatment of individual medical conditions.

Evidence-based medicine aims to promote quality research, with a focus on providing the best possible care for individual patients – on the basis of the best available data. In recent years there has also been an increasing awareness of how important it is to consider patients' individual values and principles when making treatment decisions.