The Importance of Evidence in Medicine

Dr Agrima Thakur Army College of Dental Sciences, Secunderabad

2021-11-29 05:11:03



Experience is a person’s biggest asset. Often in our daily life, our actions are dictated by the way our previous decisions panned out. With experience, we can estimate the consequences of our actions, making it easier to decide the manner in which we carry out a certain task. While two people can have similar experiences, identical experiences are hard to come across.

There is always a variation in the way different people carry out their tasks, which is owed to the difference in their experiences. Therefore, while one person may be able to carry out a task perfectly, the other may make errors causing a delay in completion of the task. This is where ‘science’ or ‘evidence’ becomes crucial.

Science, in the simplest terms, is the systematic study of the natural world through observation and experimentation. While ‘observation’ is akin to the traditional ‘experience’ that we talk about; ‘experimentation’ is the part of science which makes all the difference. Experimentation is the golden tool which gives legitimacy to scientific observations. We all know that Newton discovered gravity by observation and proved it with mathematical calculations in his book Philosophiæ Naturalis Principia Mathematica. However, it was the experiments of Henry Cavendish, carried out almost 111 years after the publication of Newton’s principia that gave Newton’s law of gravity unquestioned legitimacy and proof. When experience is supported with proof, evidence is born. The Oxford dictionary defines the term ‘evidence’ as the available body of facts or information indicating whether a belief or hypothesis is true or valid.

Evolution of evidence based medicine

Man has practiced medicine since time immemorial. Every major civilization has left traces of the way medicine was practiced in the olden days. While most of this knowledge was documented in ancient scripts, a lot of it was also passed on by word of mouth. Medicine men/ women would often learn things such as the adverse effects of administering some herbs or the technical difficulties of some surgeries from their predecessors, which was passed onto their successors. However, this way of spreading knowledge became unreliable and crude with the development of ‘evidence based medicine’.

Evidence based medicine is the practice of using available proof for making decisions for patient care. It enables better and more ethical practice, since decisions are left to the individual practitioner, who bases his/ her work on the available evidence which is a combination of experience and experimentation. Professionals who practice evidence based medicine have a solid body of literature to rely and derive inspiration from. Like in everyday life, decisions become easier to make if there is freely available, established proof on what will or will not work.

Newer evidence has caused drastic changes in the way medicine is practiced today. For example, from 1940 to 1971, Diethylstilbestrol (DES) the synthetic form of estrogen, was commonly administered to pregnant women to prevent complications such as miscarriage or premature labor. In the 1950s, new research indicated that the drug was not as effective in preventing said complications as was claimed. Further research in 1971 showed that DES caused clear cell carcinoma of the cervix and vagina. Despite these findings, the drug continued to be prescribed to pregnant European women till as late as 1978. More recently in 2011, a meta- analysis on all the data published about DES showed that DES exposure was associated with risk of many adverse health outcomes in women, such as ectopic pregnancy, miscarriage, stillbirth, preeclampsia and infertility. [1] In the present times, drugs like DES and thalidomide act as a reminder to the medical fraternity that research must never stop and newer evidence must always be promoted, since established data can also be misleading.

Before evidence was given importance, ‘expert- based medicine’ was practiced. It involved relying on the expertise of older, experienced clinicians who would dictate the approach to patient management based on the concepts they learned when in medical school and their own experiences during their years in practice. Of course, with this approach, there was limited scope for the newer ideas and innovation which generally emerged in young minds. This led to a sort of ‘stagnation’ in the field, which was eliminated once the evidence- based approach was adopted in medicine. David Sackett, known as the ‘father of evidence based medicine’ and who is credited with spreading of the evidence- based approach in UK and a lot of Europe, documented the evolution of this approach in a video. He recalls that after the adoption of evidence based medicine in district general hospitals in the UK, the young physicians realized that they could challenge their seniors in a way that was not possible with expert- based medicine. It was liberating and democratizing.” [2]

The importance of evidence during decision making

When making an important or expensive purchase, say, a new car, we tend do thorough research on the best models in the market, the safety of the car, its budget- friendliness etc. In such situations, we’re not fully convinced by solely relying on the salesperson’s opinion and therefore seek more information in order to make our decision. Knowing more information, or ‘evidence’, will help us be confident in whatever choice we make, leaving no room for regrets. Evidence based medicine is a similar exercise. The scientifically established data in literature acts as the information source and gives us an opportunity to make considered decisions for rendering better healthcare services to patients.

Evidence can also be considered as a decision making guide for young, inexperienced practitioners; since it carries within itself the trial- and- error strategy of older, experienced scientists who have now established some conclusion for all future practitioners to use. It is commonly said, ‘while it is wise to learn from experience, it is wiser to learn from the experience of others.’ In medicine, planning the treatment of a patient is a critical step, and errors due to incomplete or faulty planning can lead to heavy consequences. In such a scenario, it becomes the clinician’s first and foremost duty to make sure that the planned treatment approach is ideal for each case, if not perfect. Evidence plays a very important role in this aspect, since a quick study of the existing evidence in that particular area of treatment can eliminate the most commonly occurring errors.

For example, a junior practitioner is used to prescribing one particular brand of medication which they learned from their superior in their initial workplace. After having moved to another workplace, they find that the same medication does not show similar results on the new set of patients. Some of the patients aren’t even able to afford the medication. After consulting latest evidence, reports on the population demographic of the new area and the socio- economic strata of the patients, the junior practitioner changes his prescription to a different, maybe cheaper brand of medication which shows better results. This will be an example of holistic, evidence- based decision making causing improvement in practice.

Going through evidence before starting a case not only helps prevent unnecessary errors, but it also enables us to pick and choose the best treatment strategies and the shorter or easier, tried and tested methods for rendering patient care. This is beneficial when explaining the treatment approach to patients, since they can be assured of the results, and can also be aware of any possible complications. On the other hand, the healthcare provider saves time, effort and capital by following an established, evidence- based treatment plan. He/ she can rely upon the predictability of the technique and subsequently add to the existing literature their own experiences with the evidence- based approach they undertook.


Charles Darwin once said, ‘it is not the strongest or the most intelligent who will survive, but those who can best manage change.’ Change is inevitable, and the only way we can keep up with it is by constantly updating ourselves with the latest practices and techniques. An evidence based approach to decision making helps the practitioner remain in touch with the basic science of their profession, makes them aware of the popular techniques practiced in other geographic areas, reduces the margin of error during treatment and saves time, effort, and capital for the healthcare provider. In short, it is the best way to build a scientifically sound, efficient and successful medical practice.


[1] Hoover RN, Hyer M, Pfeiffer RM, Adam E, Bond B, Cheville AL et al. Adverse health outcomes in women exposed in utero to diethylstilbestrol. N Engl J Med. 2011 Oct 6;365(14):1304-14. doi: 10.1056/NEJMoa1013961. PMID: 21991952.

[2] Evidence based medicine— an oral history. BMJ 2014; 348 doi: