evidence-based medicine for obstetrics & gynecology
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Evidence-Based Medicine for Obstetrics and Gynecology
LIFE SCIENCES LIBRARY
Summer 2013Robin Featherstone, MLIShttp://www.slideshare.net/featherr
Why EBM?
Workshop - Objectives
By the end of the workshop, you will be able to:1. Describe the five stages of the EBM process2. Differentiate background from foreground
questions3. Develop a well-formed PICO question4. Categorize questions and identify the best studies
to answer each question type5. Select appropriate sources to search for evidence
to best answer your questions6. Identify three fundamental questions to ask when
appraising a published study
EBM for Obstetrics & Gynecology
Based on Hematology pilot EBM program for specialist residents
Focused on real-life clinical questions
Aimed to integrate EBM principles into journal clubs, everyday practice
EBM Process
Appraising the Evidence
Incorporating evidence into decision-making
Evaluating the Process
Formulating the clinical question
Searching the Evidence
Your patient for whom you are uncertain about therapy, diagnosis, or prognosis
ASK
ACQUIRE
APPRAISEAPPLY
ASSESS
Guyatt G, Rennie D, Cook D. Users' Guides to the Medical Literature : A Manual for Evidence-Based Clinical Practice (2nd Edition). New York, NY, USA: McGraw-Hill Professional Publishing; 2008.
[1.]
What are the reported incidences of paraovarian cysts?
What are risk factors for pelvic inflammatory disease?
Should a left atrial mobile mass in an elderly woman with a previous uterine sarcoma be removed?
[1.]
Sources for Background Questions• Textbooks• Handbooks• Manuals• Encyclopedias• etc
Background Questions
Patient ScenarioYou are following a 35 year-old pregnant female for low platelets thought to be due to immune thrombocytopenia as she had thrombocytopenia prior to her pregnancy. During the pregnancy, her platelets fluctuated quite a bit, ranging from her pre-pregnant baseline of 120 to as low as 60. When she presented to hospital in labour, her platelets count was 75 preventing her from getting an epidural, but ensuring a safe delivery.She undergoes a spontaneous vaginal delivery without complications. She and the baby are medically ready to leave the hospital 48 hours later. Her platelet count has risen to 110. She asked if she should be concerned for her newborn, knowing that her antibodies, the same that are causing her immune thrombocytopenia, are passed along to baby. Should a blood test be done to check the baby’s platelet count. If so, when?
Formulating a Clinical Question
Patient, population, or problem
Intervention, prognostic factor, or exposure
Comparison or intervention
Outcomes to measure or be achieved
What’s the PICO?You are following a 35 year-old pregnant female for low platelets thought to be due to immune thrombocytopenia as she had thrombocytopenia prior to her pregnancy. During the pregnancy, her platelets fluctuated quite a bit, ranging from her pre-pregnant baseline of 120 to as low as 60. When she presented to hospital in labour, her platelets count was 75 preventing her from getting an epidural, but ensuring a safe delivery.She undergoes a spontaneous vaginal delivery without complications. She and the baby are medically ready to leave the hospital 48 hours later. Her platelet count has risen to 110. She asked if she should be concerned for her newborn, knowing that her antibodies, the same that are causing her immune thrombocytopenia, are passed along to baby. Should a blood test be done to check the baby’s platelet count. If so, when?
PICO
P: Newborns born to mothers with immune thrombocytopenia
I: Blood test to check platelet count
C: No blood test
O: Diagnosis of immune thrombocytopenia
Clinical Question
In newborn patients with suspected immune thrombocytopenia, is a blood test to determine platelet count recommended to diagnose immune thrombocytopenia?
What is the “evidence”?
Systematic Reviews
Randomized control trials
Cohort studies
Case-control studies
Case reportsEditorials
Animal research
All types of articles found in PubMed
Question Best Evidence
Cost •Cost-effectiveness study
Diagnosis •Diagnostic validation studies•Prospective studies / blind comparison to a gold standard
Etiology/Harm •Cohort study•Case control study
Prognosis •Cohort study•Case control study
Quality of life •Qualitative studiesTherapy •Systematic review of Randomized Controlled
Trials (RCTs)•Single RCT
1 Heneghan, Carl, and Douglas Badenoch. Evidence-Based Medicine Toolkit. 2nd ed. Malden, Mass.: BMJ Books/Blackwell Pub., 2006.2 Glover, Jan, and Lei Wang. Find it Fast: The Clinical Question : www.med.yale.edu/library/education/guides/screencasts/finditfast/finditfast_2/
Levels of Evidencefor Therapy Question
Level of Evidence Type of Study
1a Systematic reviews of randomized controlled trials (RCTs)
1b Individual RCTs with narrow confidence interval2a Systematic reviews of cohort studies2b Individual cohort studies and low-quality RCTs3a Systematic reviews of case-control studies3b Case-control studies4 Case series and poor quality cohort and case-control
studies5 Expert opinion
15
Levels of evidence (2001). Centre for Evidence Based Medicine. Retrieved 26 Aug 2008 from http://www.cebm.net/index.aspx?o=1025
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2a 2b
543b
4
1b1b
2a
5
2b
3b
Summaries
Information Sourcesfor Diagnosis Question
Synopsis of
synthesis
1. Soundness of evidence-based approach2. Comprehensiveness and specificity3. Ease of use4. Availability
See also: http://www.jgh.ca/en/hslinteractivepyramid
Criteria for Selecting an Information Source
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Information Sourcessome examples
} includes:
• Cochrane Database of Systematic Reviews
• DARE (Database of Abstracts of Reviews of Effects)
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Information Sourcessome examples
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Information Sourcessome examples
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Information Sourcessome examples
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Expert Opinion
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Information Sourcessome examples
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Expert Opinion
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What’s the PICO?A 27-year-old presented for her initial prenatal visit at 10 weeks’ gestation. Her family and medical histories were unremarkable and she reported healthy behaviours. Her BMI was 22. She has been vegan for the previous 5 years.
Her initial prenatal labs revealed mild anemia (hematocrit, 32%; hemoglobin, 10.8 g/dL ). She was asked to bring a 3-day diet history so that her food choices could be evaluated. Evaluation of her diet revealed a deficiency of iron-rich foods and insufficient intake of foods high in folate.
You discussed iron supplementation with the patient and she expressed concern over the impact on the health of the baby.
Penney, et. al. (2008). Nutritional Counseling for Vegetarians During Pregnancy and Lactation. Journal of Midwifery & Women’s Health. Vol 53. Issue 1. pg 37-44. Retrieved July 23, 2013 from http://dx.doi.org/10.1016/j.jmwh.2007.07.003
Possible PICO 1
P: 27 year old female with prenatal anaemia
I: Iron supplementation
C: No iron supplementation
O: Adverse pregnancy outcomes
Possible PICO 2
P: 27 year old female with prenatal anaemia
I: Diet modification to include iron enriched vegetarian foods
C: No diet modification
O: Improvement in haemoglobin concentration
Possible PICO 3
P: 27 year old female with prenatal anaemia
I: Iron supplementation
C: Diet modification to include iron enriched vegetarian foods
O: Adverse pregnancy outcomes
Possible PICO 4
P: 27 year old female with prenatal anaemia
I: Iron supplementation
C: Diet modification to include iron enriched vegetarian foods
O: Improvement in haemoglobin concentration
For a patient with prenatal anemia, does iron supplementation increase the risk of adverse pregnancy outcomes?
What kind of a question is this?
Question Best Evidence
Cost •Cost-effectiveness study
Diagnosis •Diagnostic validation studies•Prospective studies / blind comparison to a gold standard
Etiology/Harm •Cohort study•Case control study
Prognosis •Cohort study•Case control study
Quality of life •Qualitative studiesTherapy •Systematic review of Randomized Controlled
Trials (RCTs)•Single RCT
1 Heneghan, Carl, and Douglas Badenoch. Evidence-Based Medicine Toolkit. 2nd ed. Malden, Mass.: BMJ Books/Blackwell Pub., 2006.2 Glover, Jan, and Lei Wang. Find it Fast: The Clinical Question : www.med.yale.edu/library/education/guides/screencasts/finditfast/finditfast_2/
Unfiltered
Expert Opinion
Filtered
Where are you going to look?
* Links to all of these resources: http://www.mcgill.ca/library/library-findinfo/subjects/health/medicine
Search strategies*
Cochrane (anemia OR anaemia) AND pregnan* AND iron
UpToDate (anemia OR anaemia) AND pregnan* AND iron > Treatment of the adult with iron deficiency anemia > Pregnancy
PubMed Clinical Queries
(anemia OR anaemia) pregnancy iron
TRIP Database (anemia OR anaemia) AND pregnan* AND iron
Google Scholar allintext: (anemia OR anaemia) ~pregnancy iron
EBM Process
Appraising the Evidence
Incorporating evidence into decision-making
Evaluating the Process
Formulating the clinical question
Searching the Evidence
Your patient for whom you are uncertain about therapy, diagnosis, or prognosis
ASK
ACQUIRE
APPRAISEAPPLY
ASSESS
Summarizing the Evidence (Systematic Reviews)*
1. Are the results valid?
A. Did the review explicitly address a sensible clinical question?
B. Was the search for relevant studies detailed and exhaustive? Were sources of evidence and search strategies specified in sufficient
detail for replication Was the likelihood and direction of publication bias considered?
C. Were the primary studies of high methodologic quality? D. Were selection and assessments of studies reproducible?
*. http://jamaevidence.com/criticalAppraisalWorksheet/26
Summarizing the Evidence (Systematic Reviews), cont.
2. What are the results?
A. Were the results similar from study to study?B. What are the overall results of the review?C. How precise were the results?
Summarizing the Evidence (Systematic Reviews), cont.
3. How can I apply the results to patient care?
A. Were all patient-important outcomes considered?B. Are any postulated subgroup effects credible?C. What is the overall quality of the evidence?D. Are the benefits worth the costs and potential risks?
1. UpToDate is a _______ resource. And EMBASE is a ________ resource.
2. The 5 stages in the EBM process are _______.3. The best evidence to answer a diagnosis
question is _______.4. To find systematic reviews of RCTs use _______.5. PICO stands for ________.6. The three questions to ask to appraise ANY study
are _______, ________, and ________.
Summary Quiz
Next steps
Some suggestions for your journal clubs (next one: August 21)Start with a patient caseDevelop a PICO questionSearch for best available evidenceAppraise the article using standard questions for
that study design
Slides available: http://www.slideshare.net/featherr
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