Evidence-Based Medicine

Definition and History of EBM

To practice the highest quality of scientific medicine, physicians must bring the best information from medical research (and medical technology) to the patient's bedside. Secondary goals are to improve the health of the public through control of epidemic diseases (whether caused by microorganisms or environmental contaminants) and comforting the patient and their immediate social group in times of illness. In the Glossary on its Web site, the Centre for EvidenceBased Medicine at Oxford University in the United Kingdom defines EBM as ‘the conscientious, explicit and judicious use of current best evidence in making [Page 362]decisions about the care of individual patients. The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research.’ The Centre also defines EBHC as an extension of EBM ‘to all professions associated with health care, including purchasing and management’ (Centre for Evidence-Based Medicine).

The practice of medicine requires physicians to make correct diagnoses and choose the best treatment to improve the health or reduce the burden of illness for their patients under conditions of significant uncertainty. The health care worker needs to effectively access the best and most current information from the medical literature, critically evaluate this information, and determine how and when the results will be applied to the patient sitting in front of them.

History of EBM

Elements of EBM can be found in the biblical Book of Daniel where a description of a trial of diet is given. The participants were Daniel's friends, and they were ‘randomized’ to eat only vegetables or the king's food. Hippocrates told the physicians of his day to observe their patients and to perform only those actions that could be helpful and would ‘first, do no harm,’ implying the ability to distinguish helpful from potentially harmful therapies. An 18th-century British physician, George Fordyce, demanded that the medical profession provide better evidence for the therapies of the day. Captain James Lind, a British naval surgeon, performed a nonblinded but randomized clinical trial on a dozen Navy seamen with scurvy. The results clearly showed that citrus was vastly superior to the other treatments being tested. Pierre Charles Alexandre Louis was a French physician who applied the new science of statistics to show that bloodletting was unlikely to benefit patients with typhoid fever.

More recently, a 1947 editorial by Austin Bradford Hill in the British Medical Journal demanded that physicians use mathematics and statistical methods to evaluate the practice of medicine. American epidemiologist John Paul in the United States coined the term clinical epidemiology in the late 1930s, but this concept was neither accepted nor used by mainstream physicians and languished in obscurity until the first modern randomized clinical trial in 1948. This trial of streptomycin for patients with tuberculosis performed under the direction of the Medical Research Council of the National Health Service in the United Kingdom showed that the therapy was beneficial. Between 1950 and the mid-1970s, further elucidation of the nature of EBM in modern medicine occurred when Dr. Alvan Feinstein differentiated the science of clinical epidemiology as distinct from the traditional epidemiology of public health. This served as the foundation of the statistical revolution in medicine beginning in the 1960s. The research of Dr. John Wennberg in the 1970s demonstrated the large variation in the quantity of health care provided to populations living in relatively small geographical areas. During this time period, there was an explosion in the number of medical research articles published. Researchers in clinical epidemiology at McMaster University Health performed outcomes and process research, and this paved the way for wider dissemination of clinical epidemiology and developed a curriculum that incorporated clinical epidemiology into the medical curriculum.

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