Transcript Evidence-based Medicine

Introduction to Evidence-based
Medicine
Tony Myers MD
7/15/00
Goals
Information Mastery
 Why we need to change
 Patient-oriented evidence (POEM)
 Keeping up

Definition of EBM

“Integrating individual clinical
expertise with the best available
external clinical evidence from
systematic research.”

David Sackett MD
The Goal

Keeping up with and critically
evaluating information so as to provide
quality patient care and feel good
about what we do.
Information Mastery
Are We Failing?

Recognizing Failures In Communication
And Learning
 Fineberg
1987: Of 28 “Landmark” trials,
only 2 had an immediate (1-2 year) effect on
clinical practice
Publication to Implementation
Antman EM, Lau J, Kupelnick B, Mosteller F, and Chalmers TC.
JAMA, 268:240-8, 1992
Lag time from time of “knowing” to
time of implementation
13 yrs for thrombolytic therapy.
 10 yrs for corticosteroids to speed fetal
lung maturity.

Are We Failing?



Ramsey P G, et al. Changes over time in the
knowledge base of practicing internists. JAMA
1991; 266:1103-7.
Sackett D L, et al, Clinical determinants of the
decision to treat primary hypertension. Clinical
Research 1977; 24:648.
Statistically and clinically significant negative
correlation between our knowledge of up-to-date
care and the years that have elapsed since our
graduation from medical school.
Fact

New types of evidence are now being
generated which, when we know and
understand them, create frequent,
major changes in the way we care for
our patients.
What Are We Doing?
CME
 Guidelines
 Experts
 Reading

Does CME Work?



Davis D A, et al. Changing physician performance.
A systematic review of the effect of continuing
medical education strategies. JAMA 1995; 274:
700-1.
Sibley J C, A randomized trial of continuing
medical education. N Engl J Med 1982; 306: 511-5.
Conclusion

Traditional CME in a nice place with pleasant after lecture
diversions is, unfortunately, completely ineffective in
changing our behavior.
What About Guidelines?

Guidelines can be very useful
 Problems
Surprise! They don’t all agree.
 Which ones do we use? (Determining
validity)
 How do we implement? (How do we
remember to do what they say?)


Once validity is established they can be an excellent
resource
The Experts ?

Remember, they’re in the same position we
are with information overload.

They often look at a patient and a disease in
a fundamentally different way because they
deal with a selected patient population.

Excellent resource once reliability has been
established.
Do We Read ?

Self-reported reading time per week.
(University setting)





Medical students
Interns
Senior residents
Fellows
Attendings graduating
 Post 1975
 Pre 1975
60 min.
none
10 min.
45 min.
60 min.
30 min.
Do We Read?
University of Virginia
 Mailing to primary care physicians

 50%
had not read a medical journal
article in the last year.
 The most commonly sited source of
information was pharmacutical
representatives.
Why Don’t We Read ?

We’re lazy?
 The
fact of the matter is that none of us
likes feeling out of date. We like it so
little in fact that we are willing to work at
night and on weekends in an effort to stay
current.

Frustration.
 Conflicting
information
 No one taught us HOW or WHAT to
read.
Running Score
Traditional CME - doesn’t work.
 Guidelines - difficult to determine
validity and difficult to implement.
 Experts - deal with a different patient
population.
 Reading - we don’t do it.

The Magic Bullet
?
Evidence-Based Medicine
“ Computer”
“ Yes Doctor”
Evidence-Based Medicine

“ I have a 65 y.o. woman with a blood
pressure of 159/92. She has
osteoporosis and mild reactive airway
disease but is otherwise healthy. What
is the best treatment for her?”
Evidence-Based Medicine
“ Since I know you are a skilled
clinician, I’m sure you confirmed the
elevated BP on at least two separate
occasions after 5 min of rest, with the
patient sitting, and with the
appropriate sized cuff.”
Evidence-Based Medicine
“ Of course. Could you speed this up.
Ms. Jones has been waiting for 10 min.
and you know how she gets when her
hemorrhoids flair.”
Evidence-Based Medicine
“Yes doctor, I’m sorry for questioning
your competence. According to a high
quality guideline, the JNC6, published
in 1997, your patient would benefit
most from education about HTN and
self-monitoring has well as a 6 month
trial of lifestyle modification including
weight reduction, exercise, moderation
of alcohol intake, decreased dietary
sodium,…”
Evidence-Based Medicine
“Yes, yes I know all that. Anything else.”
Evidence-Based Medicine
“As a matter of fact there is. If the
above measures are unsuccessful the
guideline suggests initiating a diuretic
at a low dose since this class has been
shown to decrease mortality rates from
cerebrovascular and cardiovascular
ds. It may also benefit her
osteoporosis and should have no effect
on her bronchospastic ds.”
Evidence-Based Medicine
“Thank you computer. Now start
searching for new hemorrhoid
treatments while I go see Ms. Jones”
Limits

Human
 Excellent
complex thinking skills
 Poor memory

Computer
 Excellent
memory
 Poor complex thinking skills
What Works Now
Reminder systems
 Outreach visits
 Patient education (then patients
educate their doctors)
 Conversion of local opinion leaders.

What Works Now

Shin JH, et al. Effect of problem-based, self-directed
medical education on life-long learning. Can Med
Assoc J 1993; 148: 969-76.T

Learning how to evaluate information for
relevance and validity. (Information
Mastery).
Bottom Line
We need to learn not only what to
read but how to critically evaluate
the medical literature.
Reasons For Reading
Keeping up
 Patient-specific questions (point of
care)



Information at the Point of Care: Answering
Clinical Questions, Ebell, M., JABFP, May
1999.
This is where texts online or other, reviews, and
guidelines are most useful.
The Usefulness Equation
Usefulness = Validity x Relevance
of any source
Work
Validity
The hard part of Information Mastery
 The “Truth”-Probability statement that
what we do does more good than
harm.

 Evidence-based
D. et al.
 Worksheets
Medicine, 1997, Sackett,
Determining Relevance
Will this information have a direct
bearing on the health of my patients (is
it something they care about)?
 Is the problem common to my
practice?
 If true, will it require me to change my
current practice?

Work

Basic law of human behavior: lowest
amount of work you can get away with
The Usefulness Equation
Usefulness = Validity x Relevance
of any source
Work
Relevance: Type of
Evidence

POE: Patient-oriented evidence
 mortality,

morbidity, quality of life
DOE: Disease-oriented evidence
 pathophysiology,
pharmacology, etiology
POEM
Patient-Oriented
 Evidence
 that Matters

 matters
to you, the clinician, because, if
valid, it will require you to change your
practice
Comparing DOES and
POEMs
Example
Antiarrhythmic
therapy
Antihypertensive
therapy
Screening for
prostate cancer
Disease-Oriented
Evidence
Patient-Oriented
Evidence that
Matters
Antiarrhythmic drug
X decreases PVCs on
ECGs
Antiarrhythmic drug
X increases mortality
Comment
The results of the
POEM study are
contrary to what the
DOE study would
suggest
Antihypertensive drug Antihypertensive drug The results of the
treatment lowers
treatment decreases
POEM study are in
blood pressure
mortality
concordance with
what the DOE study
would suggest
PSA screening detects Unknown whether
Although DOE exists,
prostate cancer at an
PSA screening
the important POEM
early stage
reduces mortality from is currently unknown
prostate cancer
Feeling Good About Not Knowing Everything:
Information Mastery
Prioritize efforts to identify, validate,
and apply common POEMs
 Responsibility: less to read, but more
important to find and evaluate
 Consider work factor with rare
POEMs
 Ignore and avoid rare DOEs

Keeping Up



Concentrate on “high yield” journals
with favorable POEM:DOE ratio
Scan table of contents for titles of interest
Consider three questions to determine
relevance
 Patient-oriented
 Common
to practice
 Require change of practice
Medical Journals
“Knowledge creation” vs.
“translation” journals
 Knowledge creation journals

 Good
for keeping up: temptation to
bypass
 Fountain from which all knowledge flows

Academic translation journals vs
Throw-aways
Academic Translation
Journals

Evidence-based Medicine


Evidence-based Practice


www.acponline.org/jounals/ebm/ebmmenu.ht
m
jfp.msu.edu/ebp.htm
JFP POEMS

jfp.msu.edu
High Yield Journals

> 10% POEMs: JAMA, Ann Int Med,
NEJM, JABFP, JFP, Arch Int Med, Am
J Em Med

10 or more POEMs: JAMA, Ann Int
Med, NEJM, Arch Int Med, BMJ,
Ob/Gyn
Conclusions
Read few, only if forced
 Get rid of “bedside” stack
 Use time for other things (e.g.., letters
to the editor, JFP POEMs/ACP Journal
clubs, EBM, monthly searches)

Determining Relevance
Will this information have a direct
bearing on the health of my patients (is
it something they care about)?
 Is the problem common to my
practice?
 If true, will it require me to change my
current practice?

Great Quotes
“Don’t confuse me with the facts, my
mind’s already made up”
“I wouldn’t believe this crap even if it
were true”
“When I think back on all the crap I
learned in high school, it’s a wonder I
can think at all”
"I know that most men (sic), including those at
ease with problems of the greatest complexity, can
seldom accept even the simplest and most obvious
truth if it be such as would oblige them to admit
the falsity of conclusions which they have
delighted in explaining to colleagues, which they
have proudly taught to others, and which they
have woven, thread by thread, into the fabric of
their lives.” Leo Tolstoy