EVIDENCE BASED MEDICINE
The term ‘Evidence-based
medicine’ (EBM) was coined and defined by Sackett et al in 1996 as
“The
conscientious, explicit and judicious use of the current best evidence in
making decisions about the care of individual patients”.
This further became
known as evidence-based practice which is defined as the integration of best
research evidence with clinical expertise and patient values and circumstances'
which when applied by practitioners will ultimately lead to improved patient
outcome. (Straus et al, 2005)
Best Research
Evidence means valid and clinically relevant research with a focus on
patient-centered clinical research. Clinical Expertise is the use of clinical
skills and experiences while Patient’s Values and Circumstances are the
patient’s unique preferences, concerns, and expectations in his or her setting
EBP is not only
focused on research studies but uses the experience and expertise of the
therapist and the needs of the patient in the best clinical scenarios. It is
not only to be used or understood by professionals who routinely participate in
research studies and is not a discouragement from trying new treatment.
There may be
little or no research on a particular topic or studies with small sample sizes
may have lacked the power to demonstrate statistical significance (as later
explained in the statistics section). Rothstein in 2001 said “Because RCTs
are so difficult, we will always have areas that lack evidence, we will need to
find other credible research approaches to supply evidence. Keep in mind that an absence of evidence is
different from negative evidence. An
absence of evidence is not an excuse to ignore the growing body of data
available to guide practice.”
(RCT = randomized clinical or controlled trials)
Evidence-based
physical therapy (EBPT) has been defined by Herbert, Jamtvedt, Mead & Hagen
(2005) as "physiotherapy informed by relevant high quality clinical
research"
Relevance
of EBP to Physiotherapy practice: [Adapted from Sackett et al (1997) ]
·
You
might ask questions about a range of categories of practice:
·
Assessment
– how to properly gather and interpret findings?
·
Causes
of the problem – how to identify them?
·
Deciding
what the problem is – where the symptoms/signs indicate a range of possible
problems how do you decide which is most likely?
·
How
to select and interpret tests used to identify problems and to monitor patient
progress?
·
How
to estimate the likely clinical progression of a condition/illness and any
likely complications?
·
How
to select interventions that do more good than harm and that are worth the
effort and cost of doing them?
·
How
to reduce the chance of the problem reoccurring or how to promote health?
·
How
to keep up to date; improve your skills; and run a more effective/efficient
rehab team?
·
How
best to understand the perceptions of individuals and groups e.g. service users
and carers
Goals of EBPT
Following
Evidence Based Practice Procedures Helps To:
·
Make Sure That
All Decisions Made For Patient Care Take Into Account "The Best Available
Evidence"
·
Better Plan and
Evaluate Service Delivery
·
Better Analyze
Research Studies and Direct Those Findings To Better Care
·
Take Better
Measurement and Do Interpretation Of Outcomes To Provide The Best Care Possible
·
Provide Better
Patient Information
·
Better
Understand the Reasons For Lack Of Compliance by Patients In Relation To Their
PT Care
·
Accurately Gauge
The Relationship Between Patients And Physical Therapists And Its Effect On
Health-related Outcomes.
·
Develop Theories
Based On Evidence In Practice.
Why is EBP important?
·
Clinical
decisions can be clearly explained and justified to clients and their families
·
Demonstrate
interventions are clinically and cost effective to colleagues, managers and
administration
·
Maintaining and
improving therapists’ knowledge base and the evidence base of for the future
Guiding Steps to
Practice EBP: (Straus et al,
2005)
It is foremost
important to analyze what we know and what we do not know, in relation to improving
our clinical practice. Also it is essential to form answerable questions to
address any gaps in our knowledge. EBP helps us to Search for and find the best
research evidence to address our questions and also to critically appraise the
information, based on its validity, impact or size of effect, and
applicability.
EPB helps us Integrate
information gathered from the best research evidence with clinical expertise and
the patient’s values and circumstances and Evaluate the effectiveness of any
intervention taken based on steps 1-4, and the effectiveness and efficiency of
the process
Two Fundamental
Principles of EBP
1. “Evidence
alone is never sufficient to make a clinical decision”
Consider risks
and benefits, costs, inconvenience, alternative treatment strategies, patient
preferences/values and circumstances.
2. “EBM posits a
hierarchy of evidence to guide clinical decision making”
Not all research
is equal in terms of relevance and statistical support, however, that does not
mean lower level evidence is not worthwhile.
(Guyatt and
Rennie use the term Evidence-Based Medicine, EBM; Guyatt and Rennie, 2002)
PHILOSOPHY OF
EVIDENCE-BASED PRACTICE:
PROCESS / STEPS OF
EVIDENCE-BASED PRACTICE
A] Ask:
(Formation of Clinical Question)
i) Background
Questions: Usually consist of two components, A question root (who, what,
where, when, why, how) with a verb and A condition, (test, treatment, or other
health care concern)
E.g.: What is
Osteoarthritis?
ii) Clinical
question/ Foreground question: Using the PICO Model. PICO is an acronym for the
four parts of a well-articulated clinical question:
P = Problem and/ or Patient
I = Intervention (or exposure)
C = Comparison (if relevant)
O = Outcome (including time if relevant)
[T = Time factor]
Find: Formulate the Search Strategy
PARTS OF THE QUESTION
|
CLINICAL SCENARIO
|
KEYWORDS
|
PROBLEM / PATIENT POPULATION
|
Patients undergoing Total Knee Replacement
|
Total Knee
Replacement
|
INTERVENTION
|
Post-Operative Physical therapy
|
Post-Operative
Physical therapy
|
COMPARISON (IF ANY)
|
Post-Operative Physical therapy
|
None
|
OUTCOME
|
Prevents Complications
|
Prevent
complications
|
TYPE OF STUDY
|
Randomized controlled trial
|
Randomized
controlled trial
|
Formation of
Clinical Questions Used to Search for EBP: (Guyatt and Rennie, 2002)
·
Question Type:
Categorization is useful for writing the question and statistical analysis
·
Therapy:
Evaluates the effects of various treatments or interventions
·
Harm (not
frequently investigate in PT literature): Evaluates the effects of various
treatments or modalities on function, morbidity, mortality
·
Diagnosis: Evaluates a tool or test’s ability to
distinguish among certain conditions
·
Prognosis: Evaluates the course of a certain condition
Level of Evidence in Medical
Literature:
Level
|
Criteria
|
I
|
Evidence
obtained from high-quality diagnostic studies, prognostic or prospective
studies, cohort studies or randomized controlled trials, meta analyses or
systematic reviews (critical appraisal score > 50% of criteria).
|
II
|
Evidence
obtained from lesser-quality diagnostic studies, prognostic or prospective
studies, cohort studies or randomized controlled trials, meta analyses or
systematic reviews (eg, weaker diagnostic criteria and reference standards,
improper randomization, no blinding, <80% follow-up) (critical
appraisal score <50% of criteria).
|
III
|
Case-controlled
studies or retrospective studies
|
IV
|
Case studies
and case series
|
V
|
Expert opinion
(Discussions, Seminars, Blogs etc)
|
Hierarchy of
Evidence for Treatment Decisions: (Guyatt
and Rennie, 2002)
Greatest (Top)
to Least (Bottom)
1.
Meta-analysis of
randomized controlled trial
2.
Systematic
review of randomized trials
3.
Single
randomized trial
4.
Systematic
review of observational studies addressing patient-important outcomes
5.
Single
observational study addressing patient-important outcomes
6.
Physiological
studies (studies of blood pressure, cardiac output, exercise capacity, bone
density, and so forth)
7.
Unsystematic
clinical observations
Hierarchy of Evidence
(Evidence Pyramid)
Recommendation Grades:
Grade
|
Recommendation
|
Quality of Evidence
|
A
|
Strong
|
A
preponderance of level I studies, but least 1 level I study directly on the
topic support the recommendation.
|
B
|
Moderate
|
A
preponderance of level II studies but at least 1 level II study directly on
topic support the recommendation.
|
C
|
Weak
|
A single level
II study at less than 25% critical appraisal score or a preponderance of
level III and IV studies, including statements of consensus by content
experts support the recommendation.
|
D
|
Theoretical/ foundational
|
A
preponderance of evidence from animal or cadaver studies, from
conceptual/theoretical models/principles, or from basic science/bench
research, or published expert opinion in peer-reviewed journals supports the
recommendation.
|
P
|
Best practice
|
Recommended
practice based on current clinical practice norms, exceptional situations
where validating studies have not or cannot be performed and there is a clear
benefit, harm, or cost, and/or the clinical experience of the guideline development
group.
|
R
|
Research
|
There is an
absence of research on the topic, or higher-quality studies conducted on the
topic disagree with respect to their conclusions. The recommendation is based
on these conflicting or absent studies.
|
B] ACQUIRE
Evidence Search:
Sources of Information - Where to find the research evidence, once the
foreground question is developed?
·
Internet/ World
Wide Web
·
Textbooks
·
Specific Journal
Subscriptions
·
Internet Sources
for Medical Information
I) INTERNET/ WORLD WIDE
WEB:
This category is
related to general search engines, not specific medical information journal
search sources or health-related texts and journals available on the web.
·
Provides a rapid
and abundant source of information
·
Be careful, not
all sites and sources of information meet EBP guidelines
·
Consider the
reputability of the source and the information found.
Examples: MD
Consult (fee), Google Scholar (free for the search).
Some articles
found may be free, others may have a fee.
II) TEXTBOOKS:
·
Often more
useful for answering general background questions
·
Books in print
(hard-copy) may exclude valuable recent information, due to the time taken to
compile, edit, and publish texts
·
If utilizing a
text, use one that is updated frequently and well referenced, so you can access
more details if necessary
·
Many texts that
are internet-based are becoming more evidence-based and may be an increasing
source of information for foreground questions in the future.
Examples of
internet-based texts (Guyatt and Rennie recommend UpToDate and Clinical
Evidence as becoming more evidence-based): emedicine (free), UpToDate (fee), Clinical
Evidence (fee)
III) Specific Journal
Subscriptions:
Browsing a
specific journal may be beneficial if specific to your field of practice. However,
it mostly likely will leave out many applicable articles published in other
journals. Browsing through full text journals to find a specific article with
appropriate quality and relevance often takes considerable time (Straus et al,
2005)
IV) Internet Sources
for Medical Information:
·
Systematic
Reviews or Meta-analysis - MEDLINE, Cochrane Library
·
Critically-Appraised
Topics - DynaMed, UpToDate
·
Critically-Appraised
Articles - ACP Journal Club
·
Randomized
Controlled Trials - Original articles (search MEDLINE)
·
Cohort Studies -
Original articles (search MEDLINE)
·
Case-Controlled
Studies etc. - Original articles (search MEDLINE)
·
Background
Info/Expert Opinion - Books, editorials
KEY DATABASES
PUBMED
(www.ncbi.nlm.nih.gov/PubMed).
·
Finding the
highest levels of evidence: systematic reviews and meta-analyses faster and
easier
·
Providing
further analysis of randomized controlled trials
·
When to use
Keyword search?
·
Keyword search
and limit search results for the past few months. Eg. LUMBAR DISC PROLAPSE
Setting up
Evidence-Based Filters Using my NCBI
Filters help
sort search results faster. Set up EB filters for systematic reviews,
meta-analyses, RCTs, practice guidelines
Cochrane: Cochrane Database of Systematic Reviews
PEDro: (http://www.pedro.org.au/index.html)
·
Physiotherapy
evidence-based database, produced by the Centre for Evidence-Based
Physiotherapy in Australia
·
Covers RCTs,
systematic reviews, clinical practice guidelines in physiotherapy
·
Trials rated for
quality
Sources of
Information:
·
Internet/World
Wide Web,
·
Consider the
reputability of the source and the information found.
Google:
“I personally
have found Google Scholar very helpful”. (Guyatt and Rennie, 2002)
EBSCOhost:
·
Provider of
CINAHL® (Cumulative Index to Nursing and Allied Health Literature) –
CINAHL ® also available through several other sources
·
Fee for use
(Often as a university or health science subscription):
http://www.ebscohost.com
·
Similar search
strategies to other medical information sources
APTA’s Open Door:
·
Available with
APTA membership (login to www.apta.org, look under areas of interest, research
subheading)
·
Access to
research journal collections including ProQuest, Medline, Cochrane Library,
CINAHL® (mostly contains bibliographic records, not full text journals)
·
Suggestions,
with links, for free full text (including BioMed Central, Directory of Open
Access Journals, Public Library of Science, PubMed Central, and more)
·
Tutorials and
searching tips for EBP, along with guidelines for finding full-text articles
·
Information on
PT journals and samplings of current research in specific fields
APTA’s Hooked on
Evidence:
·
Available with
APTA membership (login in to www.apta.org, look under areas of interest,
research subheading)
·
Database of
article extractions relevant to physical therapists: Peer reviewed information
about the methodological quality and level evidence of the included articles
The Guide to Physical
Therapist Practice (Text):
·
Provides PTs
with comprehensive descriptions of scope of practice
·
Details
preferred practice patterns
·
Indications for
specific tests and measures and interventions
·
APTA. Guide to
Physical Therapist Practice. 2nd ed. American Physical Therapy Association;2001.
Search Strategies
1. Key words
2. Filters
3. Bullions (Search terms): (OR, AND
4. Truncation symbols (*): Associated words
5. MeSH database (Medical Subject Heading)
6. Square brackets: [TiAb], [Au], [Ti]
C] APPRAISAL
Evaluation
Criteria – 4 STEPS
1. Credibility
(Internal Validity)
2.
Transferability (External Validity)
3. Dependability
(Reliability)
4.
Conformability (Objectivity)
Variables
Variables are characteristic
that can be manipulated or observed. They are of 2 types; Independent or
Dependent
Measurement
Scales/Levels:
]Classification is useful for communication, so that
readers are aware of the author’s hypothesis of what situation or intervention
(independent variable) will predict or cause a given outcome (dependent
variable) (Portney and Watkins, 2000)
Variables:
Independent or Dependent: (Portney
and Watkins, 2000)
Independent
Variable: A variable that is manipulated or controlled by the researcher,
presumed to cause or determine another (dependent) variable
Dependent
Variable: A response variable that is
assumed to depend on or be caused by another (independent) variable
Variables:
Measurement Scales: (Portney and
Watkins, 2000)
·
Useful to convey
information to the reader about the type of variables observed
·
Necessary to
determine what statistical analysis approach should be used to examine
relationships between variables
·
From lowest to
highest level of measurement, the scales are nominal, ordinal, interval, and
ratio
1. Nominal
Scales (Classification Scale)
·
Data, with no
quantitative value, are organized into categories
·
Categorizes are
based on some criterion
·
Categories are
mutually exclusive and exhaustive (each piece of data will be assigned to only one
category)
·
Only permissible
mathematical operation is counting (such as the number of items within each category)
·
Examples: Gender, Blood Type, Side of Hemiplegic
Involvement
2. Ordinal
Scales
·
Data are
organized into categories, which are rank-ordered on the basis of a defined characteristic
or property.
·
Categories
exhibit a “greater than-less than” relationship with each other and intervals
between categories may not be consistent and may not be known
·
If categories
are labeled with a numerical value, the number does not represent a quantity,
but only a relative position within a distribution (for example, manual muscle
test grades of 0-5)
·
Not appropriate
to use arithmetic operations
·
Examples: Pain
Scales, Reported Sensation, Military Rank, Amount of Assistance Required
(Independent, Minimal…)
3. Interval
Scales
·
Data are
organized into categories, which are rank-ordered with known and equal intervals
between units of measurement
·
Not related to a
true zero
·
Data can be
added or subtracted, but actual quantities and ratios cannot be interpreted,
due to lack of a true zero
·
Examples: Intelligence testing scores, temperature in
degrees centigrade or Fahrenheit, calendar years in AD or BC
4. Ratio Scales
·
Interval score
with an absolute zero point (so negative numbers are not possible)
·
All mathematical
and statistical operations are permissible
·
Examples: time, distance, age, weight
Measurement
Validity
Measurement
Validity examines the “extent to which an instrument measures what it is
intended to measure” (Portney and Watkins, 2000)
For example, how
accurate is a test or instrument at discriminating, evaluating, or predicting
certain items?
Measurement
Validity
Validity of
Diagnostic Tests
Based on the
ability for a test to accurately determine the presence or absence of a
condition
Compare the
test’s results to known results, such as a gold standard.
For example, a
test determining balance difficulties likely to result in falls could be
compared against the number of falls an individual actually experiences within
a certain time frame. A clinical test
for a torn ACL could be compared against an MRI.
(Portney and Watkins, 2000)
Measurement
Validity: Types
a. Face
Validity: Examines if an instrument appears to measure what it is supposed to
measure (weakest form of measurement validity)
b. Content
Validity: Examines if the items within an instrument adequately comprise the
entire content of a given domain reported to be measured by the instrument
c. Construct
Validity: Examines if an instrument can
measure an abstract concept
d. Criterion-related
Validity: Examines if the outcomes of the instrument can be used as a
substitute measure for an established gold standard test.
e. Concurrent
Validity: Examination of
Criterion-related Validity, when the instrument being examined and the gold
standard are compared at the same time
f. Predictive
Validity: Examination of
Criterion-related Validity, when the outcome of the instrument being examined
can be used to predict a future outcome determined by a gold standard
Measurement
Reliability:
·
Reliability
examines a measurement’s consistency and freedom from error
·
Can be thought
of as reproducibility or dependability
·
Estimate of how
observed scores vary from the actual scores
D] Apply:
·
Using Evidence
in Clinical Practice
·
Implementation
of the study results
·
Find out the
changes / outcome in all aspects
·
Document it
·
Bring into
discussion
·
Get a clinical
question / problem
·
For further
precision /refinement
Application of EBP to
Physiotherapy
·
Interpretation
of Evidence
·
Consider the
type of study and where the study falls on the hierarchy of evidence.
·
When evaluating
the study, ask three questions: Are the Results Valid, What Are the Results,
How Can I Apply the Results to Patient Care?
·
Don’t forget to
incorporate clinical expertise and patient values and preferences after
evaluating any research material.
Interpretation of
Evidence For Therapy/Intervention: Validity
·
Are the results
valid?
·
Were patients
randomized into the groups?
·
Was
randomization concealed (blinded or masked)?
·
Were patients
analyzed in the groups to which they were randomized?
·
Were patients in
the treatment group and control groups similar with respect to known prognostic
factors?
·
Did experimental
and control groups retain a similar prognosis after the study started?
·
Were clinicians
aware of group allocation?
·
Were outcome
assessors aware of group allocation?
·
Was follow-up
complete?
·
What are the
results?
·
How can I apply
the results to patient care?
·
Are the likely
treatment benefits worth the potential harm and cost?
Interpretation of
Evidence For Diagnosis: Validity
·
Are the Results
Valid?
·
Was there a
blind comparison with an independent gold standard applied similarly to the
treatment group and the control group?
·
Did the results
of the test being evaluated influence the decision to perform the reference
standard?
Interpretation of Evidence
For Diagnosis: Application
·
What are the
results?
·
What likelihood
ratios were associated with the range of possible test results?
·
How can I apply
the results to patient care?
·
Are the results
applicable to the patient in my practice?
·
Will the results
change my management strategy?
·
Will patients be
better off as a result of the test?
·
What are the
potential risks versus benefits of the test?
E] Evaluate your
performance as an EBPT practitioner
Ask yourself:
·
Did you ask an
answerable clinical question?
·
Did you find the
best external evidence?
·
Did you
critically appraise the evidence and evaluate it for its validity and potential
usefulness?
·
Did you
integrate critical appraisal of the best available external evidence from
systematic research with individual clinical expertise in personal daily
clinical practice?
·
What were the
outcomes of your application of the best evidence for your patient(s)?
PROCESS OF NEW
RESEARCH APPLICABILITY – 4 PHASES
1. Physiological
testing
2. Test for harm
3. Test for
effects
4. Testing
practice
Evidence V/S Experience
Based Practice in Physiotherapy
What do you
think????
EPB always
considers the experience part of the therapist. There is no application of Pure
evidence without understanding the details of the conditions based on the experiential
understanding of the patient.
IS EVIDENCE ALONE
SUFFICIENT ?????????????????????
·
Benefits
·
Risks
·
Patient values,
preferences & expectations
·
Inconvenience
·
Availability
·
Cost
effectiveness
·
Ethical &
legal issues
CONFLICTS
·
Withdrawal of
treatment procedures
·
Funds
·
Reducing the
burden of insurance companies
·
Reducing or
increasing the therapy sessions
·
Promoting one
specific therapy
·
Dominant
companies will manipulate & increase the usage through bringing favorable
results evidences
Barriers to EBP
·
Some barriers to
EBP that have been discussed in literature include:
·
Access and
availability to information
·
Limited time
·
Lack of EBP
skills
·
Confidence in
the value of the evidence
·
Support from
management
·
Conflict with
client centered philosophy of PT
However,
barriers can always be overcome:
·
Develop your own
strategies
·
Appear &
behave - professional & unique
·
Always be
conscious & aware
·
No
overconfidence
·
Update yourself
·
Emotional
stability
·
Improve your
communication skills
·
Identify your
strength & weakness
·
Do genuine &
professional practice
·
Stop requesting
for case references
·
Don’t give
clinic / referral pads to other health care professionals
·
Don’t blindly
follow the prescription
·
Develop the
habit of assessment / case discussion
·
Don’t encourage
modality prescription
·
Demand for
referral simply as physiotherapy with due respect
·
Keep on
improving the infrastructure
·
House visits
should not exploit you & your profession
·
Documentation is
mandatory - helps in professional & financial growth
·
Patient
behaviours & reactions
·
Relationship
with patients & team members
References:
1. Donald,
A. and Greenhalgh, T. (2000) A Hands-on Guide to Evidence Based Healthcare:
Practice and Implementation, Blackwell Science, Oxford.
2. Le May,
A. Evidence-base practice, London, Nursing Times Books (1999) .
3. Muir
Gray, J.A. Evidence-based Health Care. How to make Health Policy and
Management Decisions, Edinburgh, Churchill Livingstone (1997) .
4. Sackett,
D.L., Strauss, S.E., Richardson, W.S., Rosenberg, W. and Haynes, R.B. Evidence
Based Medicine: How to Practice and Teach EBM, 2nd edn,
Edinburgh, Churchill Livingstone (2000) .
5. Portney LG. Evidence-based
practice and clinical decision making: it’s not just the research course
anymore. Journal of Physical Therapy Education. 2004;18(3):46-51.
6. Sackett DL,
Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS. Evidence-based medicine:
what it is and what it isn’t. BMJ. 1996;312:71-2.
7. Kaplan SL. Et
al Developing Evidence-Based Physical Therapy Clinical Practice Guidelines.
Pediatric Physical Therapy. 2013; 257-70
8. Special Acknowledgement:
a. D. Thiagarajan MPT [Neurosciences]
b. Portea Healthcare
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