Researchers must define evidence-based

Rinckside 2003; 14,2: 5-7.

here are countless things I am completely ignorant of or that just continue to mystify me: cricket, wonder-bras, public health – the list is endless. For a long time I was also mystified by the terms “evidence-based medicine” and “evidence-based radiology”. They sounded redundant to me, like tautologies such as “wet rain”.

Medicine surely requires practitioners to possess knowledge of the evidence of appropriate diagnoses and therapies. If you lack this knowledge, or if you are unable to acquire it in a special case, you should not practice medicine or radiology. Does the introduction of a “scientific, evidence-based medicine” mean that earlier medicine was without foundation? Were patients previously treated fallaciously by incapable physicians?

I was therefore glad to see a complete session on the topic at a major conferences. But at attending that session, the mist of mystery was not dissolved but rather replaced by the fog of boredom. I learned something, though. Evidence-based medicine and radiology are apparently of Canadian descent, and the term is taken to mean keeping one’s practice up to date with an ongoing interest in research and development.

The Canadian Association of Radiologists wrote in 2001:

“The evidence-based approach was reprised, consolidated and defined as ‘evidence-based medicine’ (EBM) by physicians at McMaster University [1-3]." They continued: “Today, the more comprehensive term ‘evidence-based healthcare’ (EBHC) is commonly used because many healthcare disciplines have adopted evidence-based principles and practice. In radiology, however, these developments have received little attention [4]."

Everything is evidence-based nowadays, from herbal medicine and radiology to dental hygiene, from acupuncture and sports medicine to colon cancer screening.

Did I miss something in medical development during the last ten years? I am always cautious; therefore, for fear not being up to date, I decided to find out everything I could about evidence-based medicine, evidence-based healthcare, and evidence-based radiology.

What is Evidence?

What exactly is evidence-based medicine?

By three methods we may learn wisdom: First, by reflection, which is noblest; second, by imitation, which is easiest; and third by experience, which is the bitterest.
Confucius, 551-479 BC

The motto of medicine should be "ratio plus experience".
Friedrich Hoffmann, physician, 1660-1742

Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.
David L. Sackett et al., 1996

David Sackett and colleagues at Oxford describe it as follows:

“The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research. By individual clinical expertise we mean the proficiency and judgment that individual clinicians acquire through clinical experience and clinical practice. Increased expertise is reflected in many ways, but especially in more effective and efficient diagnosis and in the more thoughtful identification and compassionate use of individual patients' predicaments, rights, and preferences in making clinical decisions about their care.

“By best available external clinical evidence we mean clinically relevant research, often from the basic sciences of medicine, but especially from patient centered clinical research into the accuracy and precision of diagnostic tests (including the clinical examination), the power of prognostic markers, and the efficacy and safety of therapeutic, rehabilitative, and preventive regimens. External clinical evidence both invalidates previously accepted diagnostic tests and treatments and replaces them with new ones that are more powerful, more accurate, more efficacious, and safer [5]."

This new trend is essentially a mixture of continuing education, individual reading, and outcome studies. In the United States, Michigan State University’s website describes the arguments for evidence-based medicine as follows:

“Taking an evidence-based approach to practice, teaching, and research can help you address some of the limitations of current medical practice. It can help you:

spaceholder blue   stay up to date with the current literature;
spaceholder blue   communicate effectively with consultants;
spaceholder blue   make the best use of other sources of information, such as pharmaceutical representatives and colleagues;
spaceholder blue   make the best use of information from the history, physical examination, and diagnostic testing;
spaceholder blue   avoid common pitfalls of clinical decision-making [6]."

A similar explanation of evidence-based medicine is given by Dr. Martin Dawes, a lecturer at the University of Oxford. According to him, evidence-based medicine is basically the compilation of the best information available, because physicians have too many patients and are confronted by too many problems, according to Dawes There are too many journals and there is an information overload [7].

One aim of evidence-based medicine seems to be fighting information overload by training people to collect the right information. It is a way to make people process and digest information into practical knowledge.

I could not find any hard facts on special features of evidence-based medicine, even after browsing the internet and reading a number of publications. One good article clarified my understanding of evidence-based medicine and radiology as a child of the computer age and, basically, a trendy version of continuing education [8].

Where is the Evidence?

Evidence is presented at conferences by trained colleagues; however, experts have different opinions. Books and textbooks age rapidly. Journals do not cover everything, and even if you did have access to a complete selection, you would not have time to read them all. You can follow guidelines, but they may not be transparent. Or you can check the internet and PubMed for the latest news, but do you get what you want, and is the information correct?

Quality control of information posted on the internet seldom exists, and you can easily get a kind of Reader’s Digest of evidence. There is no substantiation, no confirmation whether “evidence” presented is accurate or tainted by incompetence or bias. When checking for evidence-based radiology in PubMed, I found just 10 relevant entries among the first 120 listed.

Many scientific publications are “medicine by anecdote”, even, or especially, if it is studies of new drugs. But many of these studies lack real outcome. It is all “marketing evidence”. One randomized trial cannot deliver an answer about a patient’s prognosis. One needs proper follow-up studies or systematic reviews of several randomized trials to get this information. One clinical trial might suggest an apparent benefit for patients, but five years later new facts might reveal that there was no real benefit at all.

Evidence-based medicine seems to be a very commercialized subject connected to information exploitation on the web. It also seems to be an educational tool for those physicians and nurses who have grown up and studied without major intellectual challenge: the multiple-choice and click-copy-and-paste generation.

The best solution for pointing out and presenting medical evidence are systematic reviews and synopses of primary and secondary literature, which critically appraise existing practices in diagnosis and therapy. In the evidence-based lingo this is called “research synthesis” or “meta-analysis”. You need excellent people to write these reviews – and usually it is not becoming to write such reviews if you are a well-known scientist or doctor, because it takes a lot of time to collect the relevant material and write it up. People writing such reviews are often unjustly viewed as being past the peak of their career.

Outcome Studies and CME

Evidence-based medicine is a mixture of continuing medical education, individual reading, and outcome studies.

Outcome studies focus on the results of diagnostic or, more often, therapeutic decisions. They address the consequences and effects of medical interference upon the patient, such as morbidity, mortality, and quality of life, rather than looking at instant and defined impacts such as the detection of a lesion or the significance of an antibiotic treatment.

Outcome studies try to determine the long-term consequences for the life of a patient. They are particularly important in radiology.

The tremendous increase of diagnostic examinations during the last twenty years has made it increasingly difficult and challenging to make appropriate decisions about how to interpret tests, how to choose between different tests, and how to determine when imaging is indicated. Outcome studies guide such decisions.

One prominent example of changes in radiology was the abolishment of chest x-rays in asymptomatic patients. The World Health Organization published guidelines some time ago stating that chest x-ray in such patients are of no use [9]. Evidence-based radiology has come to the same conclusion, twenty-five years later.

In other words: If you do not know about, or if you do not practice evidence-based medicine you have not missed an amazing medical breakthrough. The ideas discussed under this heading are positive, and its addition to continuing medical education, reviews, and outcome research is necessary for physicians who want to comply with the best possible quality standards in medicine.

The term “evidence-based medicine” is a catchword, however. To classify it as (the only) scientific medicine would be, euphemistically described, a terminological inexactitude. It is exploited by researchers, insurance companies, and politicians to protect their own fields of interest and financial advantages without any scientific or even “medically evident” background or benefits for patients. Often it is used to gain money or to stop money-spending, in the case of reimbursement or insurance companies.

Do not fall into the trap of fashionable balderdash.


1. Guyatt GH. Evidence-based medicine [editorial]. ACP J Club 1991(2 Suppl); 1-16.
2. Evidence-Based Medicine Working Group. Evidence-based medicine: a new approach to teaching the practice of medicine. JAMA 1992; 268: 2420-2425.
3. Sackett DL, Straus SE, Richardson S, Rosenberg WMC, Haynes BR. Evidence based medicine. How to practise and teach EBM. 2nd ed. Edinburgh: Churchill-Livingstone; 2000.
4. Anonymous. Evidence-based radiology. CAR Forum 2001; 45(2): 4.
5. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what is isn't [editorial]. BMJ 1996; 312: 71-72.
6. Michigan State University. Dept. of Family Practice, College of Human Medicine. An Introduction to Information Mastery. www.poems.msu.edu/ InfoMastery/. Accessed in August 2003.
7. Dawes M, Summerskill W, Glasziou P, et al. Sicily statement on evidence-based practice. BMC Med Educ. 2005 Jan 5; 5(1): 1.
8. Wood BP. What's the evidence? Radiology 1999; 213: 635-637.
9. Ninth Report of the World Health Organization Expert Committee on Tuberculosis. Geneva: WHO, 1974.

Citation: Rinck PA. Researchers must define 'evidence-based'. Rinckside 2003; 14,2: 5-7.

A digest version of this column was published as:
Researchers must define 'evidence-based'.
Diagnostic Imaging Europe. 2003; 19,11: 21,23,47.

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