evidence-based medicine for obstetrics & gynecology

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