This topic is very essential for Pharm.D students. It includes application, benefits, limitations of EBM. It also includes EBM history and background which helps you for examinations. EBM is very important topic in Pharmacotherapeutics-III so you may find this needful. All the best!!!

1. Sri Ramya Vaddiparthy
Evidence Based Medicine

2. Definition
.
Evidence based medicine (EBM) is the
conscientious, explicit, judicious and
reasonable use of modern, best evidence in
making decisions about the care of
individual patients. EBM integrates
clinical experience and patient values
with the best available research
information. The term was originally used
to describe an approach to teaching the
practice of medicine and improving
decisions by individual physicians about
individual patients.

3. Background & History
 Medicine has a long history of scientific inquiry about the
prevention, diagnosis, and treatment of human disease.
 The concept of a controlled clinical trial was first described in
1662 by Jan Baptist van Helmont in reference to the practice
of bloodletting-Wrote Van Helmont. The first published report
describing the conduct and results of a controlled clinical trial
was by James Lind, a Scot Naval Surgeon who conducted
research on scurvy during his time aboard HMS Salisbury in
the Channel Fleet, while patrolling the Bay of Biscay.

4.  Lind divided the sailors participating in his experiment into
six groups, so that the effects of various treatments could be
fairly compared. Lind found improvement in symptoms and
signs of scurvy among the group of men treated with lemons or
oranges. He published a treatise describing the results of this
experiment in 1753.
 An early critique of statistical methods in medicine was
published in 1835.
 The term "Evidence-based medicine" was introduced in 1990
by Gordon Guyatt of McMaster University

5. EBM Triad

6. Source

7. 5A’s of EBM

8. Principles of EBM
The practice of EBM involves five essential steps-
1)Converting information needs into answerable questions,
2) Finding the best evidence with which to answer the
questions
3) Critically appraising the evidence for its validity and
usefulness
4)Applying the results of the appraisal into clinical practice
5)Evaluating performance.

9. Step 1
 One of the difficult steps in practising EBM may be the
translation of a clinical problem into an answerable question.
When we come across a patient with a particular problem,
various questions may arise for which we would like answers.
These questions are frequently unstructured and complex, and
may not be clear in our minds. The practice of EBM should
begin with a well formulated clinical question. This means
that we should develop the skill to convert our information
needs into answerable questions. Good clinical questions
should be clear, directly focused on the problem at hand, and
answerable by searching the medical literature.

10.  A good clinical question should have four (or sometimes three)
essential components:
 The patient or problem in question
 The intervention, test, or exposure of interest;
 Comparison interventions (if relevant)
 The outcome, or outcomes of interest.

11. PICO
 Thus an answerable clinical question should
be structured in the PICO (Patient or
Problem, Intervention, Comparison,
Outcome/s) or PIO (Patient or Problem,
Intervention, Outcome/s) format

12. Step 2
 Once you have formulated your clinical question, the next step is to
seek relevant evidence that will help you answer the question. There
are several sources of information that may be of help. Traditional
sources of information such as textbooks and journals are often too
disorganised or out of date.8 You may resort to asking colleagues or
‘‘experts’’ but the quality of information obtained from this source is
variable. Secondary sources of reliable summarised evidence which
may help provide quick evidence based answers to specific clinical
questions include Archimedes , Clinical Evidence and BestBets
.Other important sources of evidence include the online electronic
bibliographic databases, which allow thousands of articles to be
searched in a relatively short period of time

13. Step 3
 After you have obtained relevant articles on a subject, the next
step is to appraise the evidence for its validity and clinical
usefulness. Although there is a wealth of research articles
available, the quality of these is variable.
 Research evidence may be appraised with regard to three main
areas: validity, importance, and applicability to the patient or
patients of interest. Critical appraisal provides a structured
but simple method for assessing research evidence in all three
areas

14. Step 4
 When we decide after critical appraisal that a piece of
evidence is valid and important, we then have to decide
whether that evidence can be applied to our individual patient
or population. In deciding this we have to take into account
the patient’s own personal values and circumstances. The
evidence regarding both efficacy and risks should be fully
discussed with the patient or parents, or both, in order to
allow them to make an informed decision

15. Step 5
 As we incorporate EBM into routine clinical practice, we need
to evaluate our approach at frequent intervals and to decide
whether we need to improve on any of the four steps. We need
to ask whether we are formulating answerable questions,
finding good evidence quickly, effectively appraising the
evidence, and integrating clinical expertise and patient’s
values with the evidence in a way that leads to a rational,
acceptable management strategy. Formal auditing of
performance may be needed to show whether the EBM
approach is improving patient care.

16. Benefits
 One of the significant benefits of EBM is that
using of the evidence based practice allows the
clinician to adapt treatment to the conditions and
risk–benefit profile of the individual patient,
which in turn, leads to better health outcomes.

17. Misconceptions
Misconception Clarification
1. EBM is “cookbook”
medicine: overly dogmatic,
inflexible, too uniform (one-
size-fits-all).
2. EBM can be based on any
reasonable evidence.
3. High-quality evidence based
on basic science and
surrogate outcomes can
reliably be used to determine
best practices for patient
care.
1. EBM is inherently meant to tailor best
evidence to the needs and preferences of a
particular patient, based on the clinical
judgement of a conscientious and capable
clinician.
2. EBM is based on best-available evidence,
which requires evaluation of all relevant
evidence and grading its quality.
3. Ideally, EBM uses patient-oriented
evidence (i.e., outcomes of importance to
patients, such as morbidity, mortality, and
quality of life) rather than disease-
oriented evidence (e.g., physiologic
variables, blood test results) when making
clinical decisions

18.  Many clinicians mistakenly believe that applying some
evidence is practicing EBM. That depends, however. What
counts is basing clinical decisions on the best available
evidence, not just any evidence. It also does not mean that we
are paralyzed when good evidence to guide us is not available.
We have all had the experience of seeing one randomized
clinical trial contradicted by another.This is especially true
when trials measure surrogate outcomes such as blood pressure
or blood glucose level rather than patient-oriented outcomes,
when study populations and interventions differ in important
ways, or when trials have different levels of intentional or
unintentional bias.

19. Applications of evidence in Clinical
Setting.
 Despite the emphasis on evidence-based medicine, unsafe or
ineffective medical practices continue to be applied, because of
patient demand for tests or treatments, because of failure to access
information about the evidence, or because of the rapid pace of
change in the scientific evidence. For example, between 2003 and
2017, the evidence shifted on hundreds of medical practices, ranging
from whether hormone replacement therapy was safe to whether
babies should be given certain vitamins to whether antidepressant
drugs are effective in people with Alzheimer's disease. Even when
the evidence is unequivocally against a treatment, it usually takes
ten years for other treatments to be adopted. In other cases,
significant change can require a generation of physicians to retire or
die, and be replaced by physicians who were trained with more
recent evidence.

20.  Physicians may also reject evidence which conflicts with their
anecdotal experience or because of cognitive biases – for
example, a vivid memory of a rare but shocking outcome
(the availability heuristic), such as a patient dying after
refusing treatment. They may overtreat to "do something" or to
address a patient's emotional needs. They may worry about
malpractice charges based on a discrepancy between what the
patient expects and what the evidence recommends. They may
also over treat or provide ineffective treatments because the
treatment feels biologically plausible.

21. Limitations
Although evidence-based medicine is regarded as the gold standard of clinical
practice, there are a number of limitations and criticisms of its use.
 Research can be influenced by biases such as publication bias and conflict of
interest in academic publishing. For example, studies with conflicts due to
industry funding are more likely to favor their product.
 There is a lag between when the RCT is conducted and when its results are
published.
 There is a lag between when results are published and when these are properly
applied.
 Hypocognition (the absence of a simple, consolidated mental framework that new
information can be placed into) can hinder the application of EBM.
 Values: while patient values are considered in the original definition of EBM, the
importance of values is not commonly emphasized in EBM training, a potential
problem under current study

22. References
 https://en.wikipedia.org/wiki/Evidence-
based_medicine
 https://adc.bmj.com/content/archdischild/90/8/837
.full.pdf
 https://www.aafp.org/afp/2018/0915/p343.html