Transcript EBM - University of Massachusetts Medical School

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The contents
this Master
module are
accurate
at the
time of publication.
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Evidence
Based
Medicine
(EBM)
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Looking beyond the hype
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Objectives
The EBM perspective on “evidence”
Critical appraisal of evidence from randomized
trials
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Issues that impact published trial results
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Considering scientific evidence and dealing with
the available information about pharmaceuticals
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Case
Your patient returns after change to a generic
medication
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The patient has concerns about taking a generic
medication and asks for another
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You need to evaluate the ad and the medication
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EVERYWHERE!
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EBM
“Evidence-based medicine is the
integration
bestMaster
research evidence
with
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clinical expertise and patient values.”
-David
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Sackett D, et al. 2000. Churchill Livingston.
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Hierarchy of Evidence
Systematic Reviews / Meta-analyses / Randomized Trials
Cohort Studies
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Cross-sectional studies
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Expert opinion
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Why are randomized trials considered
the “best evidence” for answering a
clinical question about prescribed
medications?
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(Please enter your answer below)
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Hierarchy of Evidence:
An Alternate Opinion
1. Things I believe
2. Things I believe despite the available data
3. Randomized, controlled clinical trials that
agree with what I believe
4. Other prospectively collected data
5. Expert opinion
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don’t agree with what I believe
7. What you believe that I don’t
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Bleck TP. Br Med J. 2000;321(7255):239.
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Basic Mistakes We Make in Thinking
Click
We try to confirm our
We don’t
rely on
stories
We
appreciate
Our
memories
ideas,
ratherare
than
We oversimplify
We
misperceive
thefaulty
world
rather
the role
than
ofthem
chance
statistics
question
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Kida T. 2006. Prometheus Books.
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“How important are these factors in
influencing your prescribing?”
88%
Very Important
62%
48%
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20%
4%Click
Drug
ads
to edit2%
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Drug
Patient Scientific
company preferences papers
reps
Advice Own training
from
&
colleagues experience
Avorn J, et al. Am J Med. 1982;73(1):4-8.
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Do you think you are immune to the
impact of pharmaceutical marketing?
(Please enter your answer below)
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Canada
US
Statins
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Canada
US
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Ezetimibe
Jackevicius CA, et al. N Engl J Med. 2008;358(17):1819-1828.
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1. Design
Are control and treatment
groups equivalent?
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Hildesheim A, et al. J Am Med Assoc. 2007;298(7):743-753.
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1. Design
Are control and treatment
groups equivalent?
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title style
Were patients, clinicians
and investigators blinded?
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Sprung CL, et al. N Engl J Med. 2008;358(2):111-124.
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1. Design
Are control and treatment
groups equivalent?
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title style
Were patients, clinicians
and investigators blinded?
Was measurement
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style
consistent across groups?
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Abitbol V, et al. Clin Gastroenterol Hepatol. 2007;5(10):1184–1189.
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2. Results
What were the results?
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Are they biologically valid?
Is this result clinically significant?
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What is the strength of the effect?
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Czeisler CA, et al. N Engl J Med. 2005;353(5):476-486.
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Is this outcome valid?
Magnitude (absolute risk reduction ARR)
– ARR = control event rate – treatment event rate
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Precision
– 95% confidence interval (note studies that use others like 90%)
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Berger JS, et al. Am J Med. 2008;121(1):43-49.
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Is this outcome valid?
Number needed to treat (NNT)
• NNT = 1 / ARR
= 1 / (control event rate – treatment event rate)
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Number
needed
to harm subtitle
(NNH) style
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• NNH = 1 / ARI = 1 / Absolute Risk Increase
= 1 / (intervention harm rate – control harm rate)
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Clear representation of data?
1 / ARR = NNT
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1 / .011 = 90
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90 women must
take Fosamax for 4
years to prevent 1
hip fracture
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3. Are the results relevant?
Do your patients meet the
study’s criteria?
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Did the study focus on
outcomes that you find
relevant?
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Do the treatment benefits
outweigh the potential
harm/costs?
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Issues in Relying on
Randomized Trial Results
What are
inclusion
and exclusion
criteria?
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Is your patient population represented?
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the comparison
groups
appropriate?
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style
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Issues in Relying On RCT Results
Sources of funding & potential
conflicts of interest
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Medical Device/Biotech
Firms/Pharmaceutical
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Moses H, et al. J Am Med Assoc. 2005;294(11):1333-1342.
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Catovsky D, et al. Lancet. 2007;370(9583):230–239.
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Catovsky D, et al. Lancet. 2007;370(9583):230–239.
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Association of Funding and Conclusions
in Randomized Drug Trial
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…trials funded by for-profit organizations were
significantly
likely Master
to recommend
the experimental
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drug as treatment of choice (odds ratio, 5.3) compared
with trials funded by nonprofit organizations.
Als-Neilsen B, et al. J Am Med Assoc. 2003;290(7):921-928.
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Relationships between authors of clinical practice
guidelines and the pharmaceutical industry
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Choudhry NK, et al. J Am Med Assoc. 2002;287(5):612-617.
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Issues in Relying On RCT Results
Sources of funding & potential conflicts of
interest
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Inappropriate comparison
treatments
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90% of the studies favored the sponsor’s drug
Contradictory conclusions across studies were found
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Potential sources of bias occurred
Heres S, et al. Am J Psychiatry. 2006;163(2):185-194.
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Unequivalent Treatment Conditions
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This
notMaster
an appropriate
comparison!
Richter JE, et al. Am J Gastroenterol. 2001;96(3):656–665.
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How could this study have been better
designed?
(Please enter your answer below)
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One option: Compare equivalent doses.
Esomeprazole 20 mg vs. Omeprazole 40 mg.
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Issues in Relying On RCT Results
Sources of funding & potential conflicts of
interest
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Inappropriate comparison treatments
Inadequate
to identify
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style side
effects
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Issues in Relying On RCT Results
Sources of funding & potential conflicts of
interest
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Inappropriate comparison treatments
Inadequate
power
to identify
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subtitleside
styleeffects
Statistics and publication
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Statistical Tricks
• A larger target is easier to hit
• Look at multiple subgroups until one is
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to
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found that has statistical significance
• Negative
primary
outcome
is
often
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buried, left out of reports or never
submitted for publication
Chan A, et al. J Am Med Assoc. 2004;291(20):2457-2565.
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Ryan ND. Lancet. 2005;366(9489):933-940.
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Publication
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Ross JS, et al. J Am Med Assoc. 2008;299(15):1800-1812.
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Competing Interests
Profit
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Scientific
Advancement
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Patient
Care
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Recommendations
Realize that data we use to make clinical
decisions may be affected by partisan
influences
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tocomfort
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titlebasic
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Develop
with applying
EBM
principles to all resources
Identify
quality
resources
for
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pharmaceutical information
Develop and practice skills for continuous,
self-directed, enthusiastic life-long learning
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References

Abitbol V, Briot K, Roux C, Roy C, Seksik P, Charachon A, Bouhnik Y, Coffin B, Allez M, Lamarque D,
Chaussade S. A double-blind placebo-controlled study of intravenous clodronate for prevention of steroidinduced bone loss in Inflammatory Bowel Disease . Clin Gastroenterol Hepatol. 2007;5(10):1184–1189.

Als-Nielsen B, Chen W, Gluud C, Kjaergard LL. Association of funding and conclusions in randomized drug
trials: a reflection of treatment effect or adverse events? J Am Med Assoc. 2003;290(7):921-928.

Avorn J, Chen M, Hartley R. Scientific versus commercial sources of influence on the prescribing behavior of
physicians. Am J Med. 1982;73(1):4-8.

Berger JS, Brown DL, Becker RC. Aspirin and stable cardiovascular disease. Am J Med. 2008;121(1):43-49.

Bleck TP. Alternatives to evidence based medicine. Different rating scale could be used. Br Med J.
2000;321(7255):239.

Catovsky D, Richards S, Matutes E, Oscier D, Dyer MJS, Bezares RF, Pettitt AR, Hamblin T, Milligan DW,
Child JA, Hamilton MS, Dearden CE, Smith AG, Bosanquet AG, Davis Z, Brito-Babapulle V, Else M, Wade R,
Hillmen P. Assessment of fludarabine plus cyclophosphamide for patients with Chronic Lymphocytic
Leukaemia (the LRF CLL4 Trial): a randomised controlled trial. Lancet. 2007;370(9583):230–239.

Chan A, Hrobjartsson A, Haahr MT, Gotzsche PC, Altman DG. Empirical evidence for selective reporting of
outcomes in randomized trials. J Am Med Assoc. 2004;291(20):2457-2465.

Czeisler CA, Walsh JK, Roth T, Hughes RJ, Wright KP, Kingsbury L, Arora S, Schwartz JRL, Niebler GE,
Dinges DF. Modafinil for excessive sleepiness associated with shift-work sleep disorder. N Engl J Med.
2005;353(5):476-486.

Choudhry NK, Stelfox HT, Detsky AS. Relationships between authors of clinical practice guidelines and the
pharmaceutical industry. J Am Med Assoc. 2002;287(5):612-617.
Click to edit Master title style
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References

Heres S, Davis J, Maino K, Jetzinger E, Kissling W, Leucht S. Why olanzapine beats risperidone, risperidone
beats quetiapine, and quetiapine beats olanzapine: an exploratory analysis of head-to-head comparison
studies of second-generation antipsychotics. Am J Psychiatry. 2006;163(2):185-194.

Hildesheim A, Herrero R, Wacholder S, Rodriguez A, Solomon D, Bratti MC, Schiller J, Gonzalez P, Dubin G,
Porras C, Jimenez S, Lowy D. Effect of Human Papillomavirus 16/18 L1 viruslike particle vaccine among
young women with preexisting infection. J Am Med Assoc. 2007;298(7):743-753.

Jackevicius CA, Tu JV, Ross JS, Ko DT, Krumholz HM. Use of ezetimibe in the United States and Canada. N
Engl J Med. 2008;358(17):1819-1828.

Kida T. Don’t believe everything you think. 2006; Amherst, NH: Prometheus Books.

Moses H, 3rd, Dorsey ER, Matheson DH, Thier SO. Financial anatomy of biomedical research. J Am Med
Assoc. 2005;294(11):1333-1342.

Richter JE, Kahrilas PJ, Johanson J, Maton P, Breiter JR, Hwang C, Marino V, Hamelin B, Levine JG.
Efficacy and safety of esomeprazole compared with omeprazole in GERD patients with erosive esophagitis: a
randomized controlled trial. Am J Gastroenterol. 2001;96(3):656–665.

Ross JS, Hill KP, Egilman DS, Krumholz HM. Guest authorship and ghostwriting in publications related to
rofecoxib: a case study of industry documents from rofecoxib litigation. J Am Med Assoc. 2008;299(15):18001812.

Ryan ND. Treatment of depression in children and adolescents. Lancet. 2005;366(9489):933-940.

Sackett D, Straus S, Richardson W, Rosenbert W, Haynes R. Evidence-based medicine: how to practice and
teach EBM. 2000; Toronto: Churchill Livingston.

Sprung CL, Annane D, Keh D, Moreno R, Singer M, Freivogel K, Weiss Y, Benbenishty J, Kalenka A, Forst H,
Laterre P, Reinhart k, Cuthbertson B, Payen D, Briegel J. Hydrocortisone therapy for patients with septic
shock. N Engl J Med. 2008;358(2):111-124.
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Resources
•
•
Consumer Reports Best Buy Drugs
http://www.consumerreports.org/health/best-buy-drugs/index.htm
•
•
Journal Watch
http://www.jwatch.org/
•
•
Medical Letter
http://www.medicalletter.org/
•
•
Medline (through the U.S. National Library of Medicine)
http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed
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Attorney General Consumer and Prescriber Education Grant Program Initiated Resources
http://www.rxfacts.org/
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•
Brigham & Women's Hospital
•
Georgetown University
http://www.pharmedout.org/
•
MGH Institute of Health Professionals
http://www.perxinfo.org/perx.html
•
University of Kentucky
http://www.cecentral.com/
•
University of North Carolina, Chapel Hill
http://harryguess.unc.edu/
•
University of Massachusetts Medical School/
Meyers Primary Care Institute
http://www.umassmed.edu/meyers/index.aspx
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Resources – JAMA User’s Guides
JAMA: User’s Guides to the Medical Literature. This series of 32
articles published in JAMA between 1993 and 2000 dedicated to
specific topics and now collected and expanded in the texts
above. Individual articles can be accessed through JAMA.
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• Introductions:
• Guyatt GH, Rennie D. Users' guides to the medical literature. JAMA
1993;270(17):2096-97.
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• Satya-Murti
S. Users'
Guides
to the Medical
Literature:
Essentials of
Evidence-Based Clinical Practice Users' Guides to the Medical
Literature: A Manual for Evidence-Based Clinical Practice. JAMA
2002;287(11):1464-6.
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Resources – JAMA User’s Guides
• Series:
• I. How to get started.
• II. How to use an article about therapy or prevention. A. Are the
results of the study valid?
• II. How to use an article about therapy or prevention. B. What were
the results and will they help me in caring for my patients?
•
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III. How to use an article about a diagnostic test. A. Are the results of
the study valid?
• III. How to use an article about a diagnostic test. B. What are the
results and will they help me in caring for my patients?
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• IV. How to use an article about harm.
• V. How to use an article about prognosis.
• VI. How to use an overview.
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Resources – JAMA User’s Guides
• VII. How to use a clinical decision analysis. A. Are the results of the
study valid?
• VII. How to use a clinical decision analysis. B. What are the results
and will they help me in caring for my patients?
• VIII. How to use clinical practice guidelines. A. Are the
recommendations valid?
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• VIII. How to use clinical practice guidelines. B. What are the
recommendations and will they help you in caring for your patients?
• IX. A method for grading health care recommendations.
• X. HowClick
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article
reporting
variations
in the outcomes
of
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health services.
• XI. How to use an article about a clinical utilization review.
• XII. How to use articles about health-related quality of life.
• XIII. How to use an article on economic analysis of clinical practice.
A. Are the results of the study valid?
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Resources – JAMA User’s Guides
• XIII. How to use an article on economic analysis of clinical practice.
B. What are the results and will they help me in caring for my
patients?
• XIV. How to Decide on the Applicability of Clinical Trial Results to
Your Patient.
• XV. How to Use an Article About Disease Probability for Differential
Diagnosis.
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• XVI. How to Use a Treatment Recommendation.
• XVII. How to Use Guidelines and Recommendations About
Screening.
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• XVIII. How to Use an Article Evaluating the Clinical Impact of a
Computer-Based Clinical Decision Support System.
• XIX. Applying Clinical Trial Results; A. How to Use an Article
Measuring the Effect of an Intervention on Surrogate End Points.
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Resources – JAMA User’s Guides
• XIX. Applying Clinical Trial Results; B. Guidelines for Determining
Whether a Drug Is Exerting (More Than) a Class Effect.
• XX. Integrating Research Evidence With the Care of the Individual
Patient.
• XXI. Using Electronic Health Information Resources in EvidenceBased Practice.
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• XXII: How to Use Articles About Clinical Decision Rules.
• XXIII. Qualitative Research in Health Care A. Are the Results of the
Study Valid?
• XXIII. Qualitative
Research
in Health Care
B. What style
Are the Results
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to
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and How Do They Help Me Care for My Patients?
• XXIV. How to Use an Article on the Clinical Manifestations of
Disease.
• XXV. Evidence-Based Medicine: Principles for Applying the Users'
Guides to Patient Care.
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Resources
Additional Learning Modules in This Series
 Communicating with Patients
 Organizational Influences on Prescribing
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 Pharmaceutical Development and Regulation
 Pharmaceutical Marketing
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subtitle style (PR)
 Provider-Pharmaceutical
Communication
 Links to Web-Access and Downloadable Versions Available at:
http://www.umassmed.edu/meyers/index.aspx
 Additional Resource on RCT Also Available
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Questions
1. Evidence based medicine relies exclusively on the use of published data to
treat patients.
A. True
B. False
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Answer
1. B: False.
In fact David Sacket, one of the leaders of the evidence-based medicine
movement, defines EBM as "the integration of best research evidence with
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clinical expertise and patient values." Note the three components: science,
clinical expertise and patient values.
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Questions
2. Trials funded by for-profit organizations were significantly more likely to
recommend the experimental drug as treatment of choice.
A. True
B. False
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Answer
2. A: True.
A study published in JAMA in 2003 found that, compared to those funded by
non-profit organizations, trials funded by for-profit organizations were
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significantly more likely to recommend the experimental drug as the
treatment of choice (odds ratio was 5.3).
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Questions
3. Clinical trials will often compare a new drug to a little used drug in order to
falsely inflate the efficacy of the new drug.
A. True
B. False
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Answer
3. A: True.
This is one way in which even a randomized clinical trial may not provide the
best evidence for a new treatment. Comparison drugs should be gold
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standards or standards of care.
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Questions
4. Number needed to treat (NNT) is calculated by 1/Absolute risk reduction.
A. True
B. False
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Answer
4. A: True.
Number needed to harm (NNH) is another useful calculation when
considering clinical benefit and is represented by 1/absolute risk increase.
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Questions
5. The dose of medication in the study cited to support fexofenadine’s nonsedating properties is 1/3 that of the tablet dose.
A. True
B. False
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Answer
5. A: True.
The study cited in the advertisement text uses a dose of 60 mg for the drug
in question, but the tablets themselves are 180 mg, or 3 times that amount.
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Questions
6. Interpret the following industry promotion for Ultracet:
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A. Ultracet is stronger than
Ultram.
B. Ultracet is stronger than
Acetaminophen.
C. Ultracet is stronger than
Ibuprofen.
D. Relative strength of these
drugs cannot be determined
without confidence intervals.
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Answer
6. D: Relative strength of these drugs cannot be determined without
confidence intervals.
The graph is designed to encourage the reader to believe answers A through
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C, however without information regarding statistical significance or
confidence intervals we do not know if there is any real difference between
the results reported.
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Questions
7. Publication bias may withhold important information from prescribers.
A. True
B. False
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Answer
7. A: True.
Some funders may choose not to release results because of unfavorable or
insignificant outcomes. Negative data can be helpful to prescribers, but
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many companies may not want that information to be public. The example
we used from Lancet was a review of randomized controlled trials of
antidepressants in adolescents that showed many industry-funded trials that
did not showClick
efficacy were
not published.
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UMASS MEDICAL SCHOOL
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Questions
8. In the strength of evidence pyramid, case control studies have an increased
ability to detect causality over cohort studies.
A. True
B. False
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UMASS MEDICAL SCHOOL
MEYERS PRIMARY CARE INSTITUTE
Answer
8. B: False.
Our hierarchy of evidence has systematic reviews, meta analysis and
randomized trials at the top. Under that, in descending order of quality of
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evidence are cohort studies, case-control studies, cross-sectional studies,
case reports, and expert opinion.
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UMASS MEDICAL SCHOOL
MEYERS PRIMARY CARE INSTITUTE
Questions
9. A 95% confidence interval:
A.
B.
C.
D.
Is significant if it crosses 0.
Estimates the range of the true effect.
Has no relationship to the number of patients studied.
Is stronger with a wider range.
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UMASS MEDICAL SCHOOL
MEYERS PRIMARY CARE INSTITUTE
Answer
9. B: Estimates the range of the true effect.
The confidence interval is an estimate of the range within which the true
effect lies. There are two pieces to evaluate with a confidence interval. The
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first is the width of the confidence interval. This is determined by the number
of patients studied and the variability within the data. Narrower ranges are
better.
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The next point to consider is whether the interval includes the null
value. The null value is the measure that indicates no association between
intervention and outcome. Any confidence interval that includes the null
value allows "chance" as an explanation for the results found.
UMASS MEDICAL SCHOOL
MEYERS PRIMARY CARE INSTITUTE
Questions
10. What factors should you consider in determining whether a study’s results
are relevant to your patient?
A.
B.
C.
D.
The study was conducted with a similar population.
The study outcomes are relative to your patient.
Data suggests the benefits are likely to outweigh the risks.
All of the above.
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UMASS MEDICAL SCHOOL
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Answer
10. D: All of the above.
All of the answers help you to determine whether and how to apply study
results to your patient. Taking the answers one at a time, A) if a study
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population is very different from your patient (in age, race, gender, co-
morbidities, etc) your patient may have a different outcome on the same
medication; B) recall that the application of evidence-based medicine
requires that Click
the provider
integrate
patient values
into treatment
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C) as we know, all medications carry some risk, balancing those to
determine whether the benefits outweigh the risks for your patient is an
important step in decision-making.
UMASS MEDICAL SCHOOL
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Questions
11. Did completing this module help you to identify issues that impact
published trial results?
A. Yes, definitely
B. Yes, probably
C. Probably not
D. Definitely not
E. Not sure
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12. Would you recommend this training module to a colleague?
A. Yes, definitely
B. Yes, probably
C. Probably not
D. Definitely not
E. Not sure
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UMASS MEDICAL SCHOOL
MEYERS PRIMARY CARE INSTITUTE
Questions
13. Will you do anything differently in your practice as a result of this training
module?
A. Yes, definitely
B. Yes, probably
C. Probably not
D. Definitely not
E. Not sure
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14. Please tell us about any changes you are considering or planning:
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