Dr. Dileep Bhale

Guest Lecture


Medicine is an ever-changing science. As new research and clinical experience broaden our knowledge, changes in delivery of healthcare are required. The greatest change in medical practice over the last two centuries has been the replacement of empiricism with scientific method. Research is going on in hundreds of laboratories and hospitals around the world and so much research is now published each week that it takes years for the results to be adopted in clinical practice. Healthcare workers therefore practice with restricted resources and are unable to keep abreast of the knowledge of best practice hidden in the literature. The scientific basis of clinical practice is thus far behind that of clinical research.

Seeking an evidence base for medicine is as old as medicine itself, but in the past decade or so the concept of evidence-based medicine is focusing attention on the application of evidence from valid clinical research to clinical practice. Although current clinical practice is evidence based, important new evidence from research often takes a long time to be implemented in daily practice. It is seen that many times established practices persist even if they have been proved to be ineffective or harmful. Many clinicians struggle to apply the results of studies that do not seem relevant to their daily practice.

Evidence Based Medicine (EBM) has been defined as the "conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patient. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research". This is the most common definition of EBM and has been taken from David Sackett.

It can be seen that EBM is the integration of clinical expertise, patient values and the best evidence in to decision-making process for patient care. The evidence itself does not make a decision for you, but it can help support the patient care process. The full integration of these three components in to clinical decision making enhances the opportunity of optimal clinical outcomes.

Steps in the EBM Process

Evidence Based Practice (EBP) is often the term used for the practice of EBM. It is usually triggered by clinical encounters with patients that generate questions about the effects of therapy, the utility of diagnostic tests, the prognosis of diseases or the etiology of diseases.

Following are the steps of EBP :

The patient : Start with the patient - a clinical problem or question about the care of the patient

The question : Construction of a well built clinical question derived from the case

The resource : Select appropriate resources and conduct a search

The evaluation : Appraisal of the evidence for its validity and applicability

The patient : Return to the patient - integrate the evidence with clinical expertise, patient preferences and apply it to practice

Self-evaluation : Evaluate your performance with this patient

It is clear that EBM requires new skills of the clinician like efficient literature searching and application of formal rules of evidence in evaluating the literature. EBP is a process of lifelong, self-directed, problem-based learning in which caring for one's own patients creates the need for clinically important information about diagnosis, treatment and other clinical and healthcare issues.

Clinicians need some training for the search process. A good tutorial about searching "PubMed" is available at the National Library of Medicine website.

Another important part of the EBM process is evaluation of the literature. This again needs introduction to some basic research methodologies. Many resources about the evaluation process are available on the web; link to a tutorial on EBM is given at the end. There are levels of evidence based on strength of statistical validity and research design; they are as follows, 1 being the strongest evidence;

  1. Systematic reviews and meta analysis. 

  2. Randomised controlled trials.

  3. Cohort studies. 

  4. Case control studies. 

  5. Cross sectional surveys.

  6. Case reports

Evidence Based Medicine: Common Criticisms

Clinicians have always striven to combine their clinical expertise and their patients' values with the best available evidence. However the coining of the term evidence-based medicine in the early 1990s has led to demands for teaching of EBM at undergraduate and postgraduate levels. It has also led to criticism of the practice of EBM.

The criticisms of evidence based medicine may be classified as "limitations universal to the practice of medicine", "limitations unique to evidence based medicine" and "misperceptions".

Universal to the practice of medicine

Shortage of coherent, consistent scientific literature

Difficulties in applying evidence to the care of individual patient

Barriers to the practice of high quality medicine

Unique to EBM

The need to develop new skills

Limited time and resources

Paucity of evidence that EBM "works"


EBM denigrates clinical expertise

It ignores patients' values and preferences

It promotes a cookbook approach to medicine

It is simply a cost-cutting tool

It is an ivory-tower concept

It is limited to clinical research

It leads to clinical nihilism in the absence of evidence from randomized trials


These are some of the links where you can learn more about evidence-based medicine.

A good tutorial on evidence based medicine :


A tutorial for searching National Library of Medicine database using "PubMed":


NHS centre for reviews and dissemination:


Centre for Evidence Based Medicine :


Bandolier, an EBM site:


POEMs another EBM site:


Cochrane centre for Evidence Based Medicine:


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