Year : 2000 | Volume
: 17 | Issue : 1 | Page : 73--78
Evidence-based medicine: The new paradigm of clinical decision making
Department of Urology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
Department of Urology, JIPMER, Pondicherry - 605 006
Traditional clinical decision making (Opinion-Based Medicine or The Old Paradigm) is based on individual clinical experience. Wide variability and inconsistencies of traditional clinical decision making have been documented. The movement of Evidence-Based Medicine (The New Paradigm) was started in early 1990s to integrate research evidence into clinical decision-making process with the ultimate aim of providing optimum management to patients. This article briefly discusses the shortcomings of Opinion-Based Medicine and describes the principles, methodology, requisite skills and resources, advantages and limitations of Evidence-Based Medicine.
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Kumar S. Evidence-based medicine: The new paradigm of clinical decision making.Indian J Urol 2000;17:73-78
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Kumar S. Evidence-based medicine: The new paradigm of clinical decision making. Indian J Urol [serial online] 2000 [cited 2021 Sep 22 ];17:73-78
Available from: https://www.indianjurol.com/text.asp?2000/17/1/73/41030
Traditional clinical decision making (Opinion-Based Medicine or The Old Paradigm) is based on individual clinical experience. ,, Studies have documented wide variability and inconsistencies of traditional clinical decision making. ,, This is largely due to the formidable task of keeping up with fast-growing medical literature and resulting gap between medical research and clinical practice. ,, The movement of Evidence-Based Medicine (The New Paradigm) was started in early 1990s to integrate research evidence into clinical decision making process with the ultimate aim of providing optimum management to patients. ,, This article defines Evidence-Based Medicine and discusses its methodology. Resources and skills necessary to practise Evidence-Based Medicine and its advantages and limitations are also described.
Opinion-Based Medicine (The Old Paradigm)
In Opinion-Based Medicine, clinical decisions are made by the seniormost clinician of the group [Figure 1]. The senior clinician uses personal experience, clinical intuition and anecdotal evidence for decision making. This traditional clinical decision making is based on the following assumptions: 
Individual clinical experience provides the foundation for diagnosis, treatment and prognosis. The authority of an opinion is directly related to the volume of clinical experience.Clinical experience and judgement enables clinicians to evaluate new tests and procedures.
Studies in 1980s revealed wide geographical variations in the rates of prostatectomies,  carotid endarterectomies, tonsillectomies and hysterectomies. , As it could not be explained by the rates of disease occurrence, it obviously reflected inconsistencies and shortcomings of the clinical decision making of Opinion-Based Medicine. The documentation of the wide variability of clinical practice was one of the factors that prompted the evolution of EvidenceBased Medicine in the early 1990s at McMaster University in Hamilton, Ontario. ,,
Evidence-Based Medicine (The New Paradigm)
Evidence-Based Medicine uses scientific evidence for clinical decision making with the ultimate aim of providing optimum management to patients. It is defined as the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.  Evidence-Based Medicine rests on the following assumptions: 
Systematic, reproducible attempts of research studies to record outcomes increase the certainty of diagnosis, treatment and validity of diagnostic tests.Formal rules of scientific evidence  are essential to evaluate the literature on diagnosis, treatment and prognosis. These rules are embodied in the discipline of clinical epidemiology. 
The basic principles of Evidence-Based Medicine include the following: 
Clinical decisions should be based on the best available scientific evidence.Clinical problems should determine the type of evidence to be sought.The best evidence is identified by using epidemiological and biostatistical concepts.Conclusions derived from the critical appraisal of evidence should be used for the management of patients.Clinical performance should be constantly evaluated.
Evidence-Based Medicine does not prescribe the types of diagnostic or intervention procedures that clinicians should use in practice. It is a toolbox consisting primarily of methods designed to integrate research study evidence into the clinical reasoning process. 
The Methodology of Evidence-Based Medicine
The methodology of Evidence-Based Medicine comprises the following steps: 
Formulation of clinical questions from patient problems.Performing an electronic search of literature for relevant evidence.Evaluation of evidence for its validity and usefulness.Use of valid and applicable evidence in clinical practice.
These steps of clinical decision making in EvidenceBased Medicine are depicted in [Figure 2].
Evidence-Based Medicine serves as a bridge between medical research and clinical practice [Figure 3]. In Opinion-Based Medicine a gap remains between medical research and clinical practice because it is a formidable task to keep up with the medical literature due to the following barriers: 
There is continuing rapid proliferation of medical literature.Journal articles are widely disseminated and poorly-organised.There is a lack of time necessary for keeping up to date.Textbooks become quickly outdated.Most of the available information is unsuitable for clinical decision-making due to lack of validity and applicability.
The methods of keeping up with medical literature differ in Opinion-Based Medicine and Evidence-Based Medicine [Table 1].
1. Formulation of Clinical Questions from Patient Problems.
A clinical question is formulated around a clinical task in such a manner that the question can be answered through a systematic search for relevant evidence. Clinical tasks include making a differential diagnosis, selecting diagnostic tests, predicting prognosis, selecting therapy and determining etiology of disease. Clinical questions should be specific and should include the type of patient, the clinical intervention and the clinical outcome of interest. 
2. Performing an Electronic Search of Literature for Relevant Clinical Articles.
An electronic search of Medline is carried out using CD-ROM or the Internet. ,,,,, If the search is confined to only Medline, as many as 50% of relevant articles may be missed. Literature search can be improved by improving search strategy and by using other databases such as Embase and Controlled Clinical Trials Registry of The Cochrane Collaboration.
3. Evaluation of Evidence for its Validity and Applicability.
Most of the published articles either contain methodological flaws or lack clinical applicability. Hence, the quality of evidence is evaluated or critically appraised using criteria recommended in the Users' Guides to the Medical Literature in JAMA ,,,,,, and other publications.  By critical appraisal, articles providing valid, important and applicable evidence are selected [Figure 4].
For critical appraisal of different types of studies, "hierarchy of evidence"  is used in which the highest weight is assigned to systematic reviews and meta-analyses and the lowest weight is assigned to case reports [Table 2].
4. Use of Valid and Applicable Evidence in Clinical Practice.
Evidence which has been identified as valid and applicable is used to solve patient problems. This evidence can be stored for future use also.
Skills Necessary for Evidence-Based Medicine
The practice of Evidence-Based Medicine needs the following skills:
Ability to use computers.
Ability to use the Internet.
Ability to perform efficient medical literature search.
Ability to critically appraise journal articles.
a) Ability to evaluate research designs.
b) Ability to evaluate statistics in an article.
c) Ability to interpret research study results.
Ability to make recommendations based on the strength of evidence.
Resources Necessary for Evidence-Based Medicine
Following resources are necessary for the practice of Evidence-Based Medicine:
Round-the-clock access to a computer with a CD ROM drive, Internet connection and a printer.Medline and other databases on CD-ROM.Evidence-Based Medicine textbooks and journals.
Advantages of Evidence-Based Medicine
The advantages of Evidence-Based Medicine include the following: 
It helps in providing optimum management to patients.It promotes self-directed learning.It encourages research in areas where scientific evidence is lacking.
Limitations of Evidence-Based Medicine
The limitations of Evidence-Based Medicine include the following: 
The resources necessary for the practice of EvidenceBased Medicine are expensive.Learning and practising Evidence-Based Medicine are time consuming.Randomised controlled trials may not be available in many surgical fields.Evidence-Based Medicine may be perceived as a threat by authoritarian clinicians.
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