What is “evidence-based medicine”?
The term evidence-based medicine was developed by Professor Gordon Guyatt in 1990 at McMaster University in Hamilton, Ontario while he was preparing a document for applicants to the International Medicine residency program.1 Even though the term evidence-based medicine may seem to be fairly new, its overall teachings and fundamentals have been around for many centuries.
Evidence-based medicine is defined as the systematic approach to finding and analyzing published data for the 4basis of clinical decision making.1, 2 This concept is very important for physicians as they are required to use current research findings and data to diagnose and treat patients. Though, due to the quick pace of modern day research, keeping up with current research findings may be a challenging and daunting task. This is where evidence-based medicine comes in, as it effectively bridges the gap between modern day research and physician.1
Essentially, evidence-based medicine is about asking important questions based on the patients needs, finding and appraising the relevant data, then using the data and conclusions in every day clinical practice.
Through the ages of evidence-based medicine
There are three main periods of the development of evidence-based medicine, each of which made a unique contribution to the modern day approach of evidence-based medicine. The first period is known as the ancient era.
Ancient era
The ancient era involved the use of anecdotes which were transmitted primarily through authoritative means and through stories. The concept of evidence-based medicine was loosely termed during this time period.2 An example, can be seen in biblical accounts of healing:
Then Daniel said to the guard, “Eat only vegetables and drink only water for ten days. Then compare your looks with that of young men and be guided in your treatment 5by what you see.” The guard listened to what Daniel said and tested it for ten days. At the end of the ten days he looked healthier and was better nourished than all the young men.2
In this example, one can loosely see the modern teachings of evidence-based medicine through biblical accounts. Daniel is providing a treatment to the guard's disease based on the guard's symptoms.
Renaissance era
The renaissance era began during the 17th century and it coincided with challenges and objections to popular theories.2 Also, during this time period, one could see the development of journals and textbooks which contained various conclusions of research findings. At this point in time, there are two clear examples of evidence-based medicine: bloodletting and scurvy.
- BloodlettingBloodletting is the removal of high quantities of blood from an individual to help prevent or cure disease. The concept dates back to the Egyptian era and it spread to the Greeks and Romans.3 This concept was beginning to be questioned near the 17th century. Despite the disputes, challenges, and conflicting data over bloodletting, brochures and pamphlets were still being written regarding its use and advantages.2,3 Near the end of the 19th century, the practice of bloodletting vanished as it was deemed an ineffective tool against disease.3
It is very important to realize the connection between bloodletting and evidence-based medicine. Through the 616th and 17th century, bloodletting was a common tool used to cure disease and illness, though once research refuted its claims, the practice diminished. Most importantly, due to conflicting evidence, physicians stopped the use of bloodletting.2 This shows the importance of keeping current with new findings in research.
Interestingly enough, even though evidence against bloodletting was found in the 17th century, it was still used until the late 19th century. This brings about another important characteristic of evidence-based medicine which deals with the fact that evidence is neither easily nor rapidly translated into practice. Once again, it is ultimately up to the physician to keep up with current research findings.
- ScurvyToday, we know that scurvy is a disease caused by prolonged deficiency in vitamin C. It is a disease that can lead to anemia, ulceration of the gums, and hemorrhages into the skin.4
An interesting story involving the discovery, prevention and cure of the disease is very important in the renaissance era of evidence-based medicine. Interestingly enough, the disease was discovered and cured at sea during the 1700s by a physician turned sailor known as Dr James Lind.2, 5 While at sea, there was a lack of fruits and vegetables to eat and thus, the sailors would not get the proper nutrients they needed.2 Most often, the sailors had rotting gums, weak knees, and were often very sick. Lind then decided to experiment on his fellow crew members by giving each of them something different to eat. 7Some were given nutmeg, while others were given lemons and oranges.2, 5 After six days of duty, Lind saw sudden and visible positive effects on the patients who ate lemons and oranges.5 From this simple experiment he concluded that lemons and oranges were the best treatment for distemper (scurvy) at sea.
How does this relate to evidence-based medicine? At first, due to a lack of data, the use of lemons and oranges as a cure for scurvy was limited and remained speculative. However, due to his discovery, clinical trials were conducted and evidence was gathered. Scurvy became better understood and treatments became incorporated in clinical practice.2 This was one of the first moves away from clinical expertise and towards evidence-based medicine.
Transitional era
The transitional era began during the mid to late 19th century, and lasted till about the 1970s. A very important individual in this era is Ernest Amory Codman who has been called the pioneer of evidence-based medicine.6
Codman was important in the development of a concept known as “the end result.2” Essentially, the idea behind the end result was that hospitals should follow up with patients who have been treated, for long enough, to determine if the treatment was successful.2, 6 If the treatment was unsuccessful then the physician should ask themselves why the treatment was unsuccessful with the overall goal of preventing failure in the future. Codman's methodology worked by the development of 5 inch by 8 inch cards that surgeons would use to write 8characteristics of the patients before and after treatment.6 This card was then brought back to the hospital one year later and the treatment was evaluated on the terms of overall success. This was extremely important as this provided hospitals with a means to compare the various treatments given by surgeons for surgeries and to determine which were the most efficient and successful.2,6
Initially, Codman's ideas were very controversial due to the fact that a surgeon's success was measured by status and seniority rather than the outcomes of surgery and success rate. Though in modern medicine, Codman's concepts were nothing short of brilliant in the development of evidence-based medicine. Due to Codman's work, registries were created to record outcomes of research and establish important standards. This was very important in the modern era of evidence-based medicine.
Evidence-based medicine and the modern era
The modern era of evidence-based medicine begins during the mid to late 20th century with the involvement of two important figures: Archie Cochrane and David Sackett. This era was very important for evidence-based medicine as it lead to the biggest development of what we now know as randomized controlled trials (RCT) (B1).2, 7 Cochrane was effectively the first to show the importance, significance, and effectiveness of using RCTs for assessing treatments.2 His work led to the formation of the Cochrane Center, which later became known as the Cochrane Collaboration. The Cochrane Collaboration (B2) is very 9important in evaluating, monitoring, and producing RCTs in almost all areas of medicine.2 Also, as you will learn later in this book, the Cochrane Collaboration is very important in the further evaluation and production of systematic reviews of health care intervention as well as the promotion for the use of clinical trials.
Another important figure in the modern era of evidence-based medicine is David Sackett. He is effectively credited for defining evidence-based medicine.2 Without him, who knows where we would be!
Important Learning Points
- The term evidence-based medicine was coined by Gordon Guyatt at McMaster University in Hamilton, Ontario.
- There are three main eras of evidence-based medicine: The ancient era, the transitional era, and the renaissance era.
- The modern era of evidence-based medicine involved two important figures, namely, Archie Cochrane and David Sackett.
Definitions
B1. | Randomized control trials (RCTs): A study design to determine a cause-effect relationship between treatment groups and/or control group. RCTs involve randomization process to assign patients to each group. |
B2. | Cochrane Collaboration: A non-profit organization that aims to provide current and readily available health care information worldwide. |
REFERENCES
- Historical perspectives of clinical research. In: Bhandari M & Joensson A (Eds.) Clinical Research for Surgeons. Thieme Publishing Group, New York 2009.
- Claridge JA, Fabian TC. History and development of evidence-based medicine. World Journal of Surgery 2005;29:547–53.
- Power D. The decay of blood letting 1909. The Practitioner 2009;253:1717.
- Glouberman S. Knowledge transfer and the complete story of scurvy. Journal of Evaluation in Clinical Practice 2009;15:553–57.
- Doherty S. History of evidence-based medicine. Oranges, chloride of lime and leeches: Barriers to teaching old dogs new tricks. Emergency Medicine Australasia 2005;17: 314–21.
- Kaska SC, Weinstein JN. Ernest Amory Codman, 1869–1940: A pioneer in evidence-based medicine. Spine 1998;23:629–33.
- Worrall J. What is evidence in evidence-based medicine. Philosophy of Science 2000;69:S316–S30.