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Megan von Isenburg
May 5, 2017
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 2
EBM Basics:
- What?
- Why?
Study Design
- Hierarchy
- Searching
Randomized
Controlled Trials
- Randomization
- Critical appraisal
- Math
Image from Pexels
Study Designs
3
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 4
Shared Decision
Making
EBP the Basics: Study Design and Randomized Controlled Trials. 2017 5
Study
Design
1. Describe the studies used in
clinical
medicine
2. Identify the strengths /
weaknesses
3. Identify search
strategies in
PubMed
4. Identify study designs
from article
abstracts
Cookie-cutter medicine?
Following guidelines?
A bunch of algorithms in an EHR?
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 6
7
Assess
Ask
AcquireAppraise
Apply
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 8
P
I
C
O
Patient Problem, Population
Intervention, prognostic factor
Comparison
Outcome
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 9
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 10
Background◦ General knowledge
◦ What are the clinical manifestations of…?
Foreground◦ Seek specific knowledge to inform clinical
decisions
◦ In pediatric patients with rhinitis, are intranasal steroids more effective than antihistamines?
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 11
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 12
The better the
evidence the
more confidence
in the decision
Patient
values and
preferences
matter
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and Randomized Controlled Trials. 201713
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 14
OBSERVATIONAL
RCT COHORT
CASE CONTROL
EXPERIMENTAL
ANALYTICALDescriptive
CROSS
SECTIONAL
QUALITATIVE
CASE
REPORTS
OBSERVATIONAL
RCT COHORT
CASE CONTROL
EXPERIMENTAL
ANALYTICAL
15EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Is this EXPOSURE
(Intervention, prognostic factor, test, or study
factor)
Associated with this Disease or
OUTCOME
16EBP the Basics: Study Design and Randomized Controlled Trials. 2017
17EBP the Basics: Study Design and Randomized Controlled Trials. 2017
18EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and Randomized Controlled Trials. 201719
Starts with patients with an
OUTCOME
and looks back to an
EXPOSURE
20EBP the Basics: Study Design and Randomized Controlled Trials. 2017
EXPOSURENo
Cell phone usage
EXPOSURECell phone usage
OUTCOMENo Brain Tumors
21
OUTCOMEBrain
Tumors
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
22EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Cheap
Quick
Rare outcomes
Ethical
Recall Bias
Confounders
Difficult to choose
control groups
a variable that is associated with both the
exposure and disease and could provide an
alternative explanation for why an exposure is
associated with a disease in a study.
http://theebmproject.wordpress.com/fundamentals/study_design/study-validity/
23EBP the Basics: Study Design and Randomized Controlled Trials. 2017
24EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Confounder: obesity
Cases
Controls
TIME
Case-Control Study
Exposure
Absent
Exposure
Present
Measure HERE
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 26
Starts with patients with an
EXPOSURE and
follows them forward to
an OUTCOME
27EBP the Basics: Study Design and Randomized Controlled Trials. 2017
28
EXPOSURE
NO HRT
EXPOSURE
HRTOUTCOMENo Heart Disease
OUTCOMEHeart
Disease
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
Self Select
29EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Ethical
Establish timing
Prospective
Show association
Time Consuming
Confounders
30EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Confounder?
Outcome
Yes
Outcome
No
Exposure
Absent
TIME
Cohort Study
Exposure
Present
Measure HERE
Framingham Heart Study
NHANES Studies
Black Women’s Health Study
Nurses Health Study
Physician’s Health Study
Avon Longitudinal Study of Parents and Children (ALSPAC)
32EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Cohort - Starts with patients
with an EXPOSURE and
follows them forward to
an OUTCOME;
Retrospective - All the data has
already been collected
33EBP the Basics: Study Design and Randomized Controlled Trials. 2017
EXPOSUREMI Admitted
weekday
EXPOSUREMI Admitted
weekend
2010-2013
Database
34
OUTCOMEIn-HospitalMortality
OUTCOMENo
In-HospitalMortality
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
35EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Ethical
Establish timing
Data already
collected
Confounders
Data collected
before research
question
Retrospective Cohort Study
Outcome
Yes
Outcome
No
TIME
Exposure
Absent
Exposure
Present
Measure HERE
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 37
Start with patients who are
randomized to an EXPOSURE
and follows them forward to
an OUTCOME
38EBP the Basics: Study Design and Randomized Controlled Trials. 2017
39EBP the Basics: Study Design and Randomized Controlled Trials. 2017
40
EXPOSURE
NO HRT
EXPOSURE
HRTOUTCOMENo Heart Disease
OUTCOMEHeart
Disease
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
Randomized
41EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Confounder?
42EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Controls for bias
Balanced groups
Proves efficacy
Expensive
Ethical issues
Time consuming
TIME
Cure
No
Cure
Drug
Placebo
Randomized Controlled Trial
Measure HERE
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 44
Focuses on a clinical question
Conducts a thorough literature search
Validates credibility of the studies
Summarizes the data
45EBP the Basics: Study Design and Randomized Controlled Trials. 2017
AUTHOR'S CONCLUSIONS:
This systematic review,
incorporating the latest available
trial data, shows that hormone
therapy does not significantly
change the risk of all-cause
morality, CHD death or non-fatal
AMI but increases the risk of
stroke in postmenopausal
women.
46
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
47
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
48EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Summarizes
studies
Validates smaller
studies
Generalizability
Saves time
Time Consuming
Publication bias
Heterogeneity
Case Control
Retrospective Cohort
Cohort
Randomized Controlled Trial
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 49
50EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Descriptive
CROSS
SECTIONAL
QUALITATIVE
CASE
REPORTS
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 51
A report of a single unique or
unusual case or a number of
similar cases
52EBP the Basics: Study Design and Randomized Controlled Trials. 2017
53
ExposureLavender
OUTCOMEEnlarged Breasts
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 54
20172010 2019
EXPOSURE
OUTCOME
55EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Brings to attention
unusual case
Start of research
Observation
No control
No association
No comparison
Randomized Controlled
Trials
Cohort Study
Case Control Study
Meta -analysis
Systematic reviews
Cross Sectional
Case Reports/Case Series
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 56
Both EXPOSURE and
OUTCOME are measured
simultaneously in a given
population
57EBP the Basics: Study Design and Randomized Controlled Trials. 2017
58
EXPOSURENew Test
AndGold Standard
Test
OUTCOMESensitivity/
Specificity of New Test
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
59EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Shows accuracy
of new test
Calculate
likelihood ratios
Expensive
Ethical issues
60
OUTCOMEDoctor’s visit
EXPOSUREApple a day
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 61
20172010 2019
EXPOSURE
OUTCOME
62EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Cheap
Easy
Ethical
Recall Bias
Confounders
Addresses questions related to the
human response to health issues.
Describes, explores and explains
human behavior.
63EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Qualitative study
64
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
Qualitative study
Based mainly on their
family history and
lifestyle, women do
not generally
consider themselves
to be at personal risk of heart disease.
Ballard K. Understanding risk: women's perceived risk of menopause-
related disease and the value they place on preventive hormone
replacement therapy. Fam Pract. 2002 Dec;19(6):591-5. PubMed
PMID: 12429660.
65
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
66EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Documents the
human experience
Motivations
Explains behavior
Poorly understood
Lack of objectivity
Lack of
Generalizability
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 67
Why is this important?
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 68
The better the
evidence the
more confidence
in the decision
Patient
values and
preferences
matter
P
I
C
O
T
T
Patient Problem, Population
Intervention, prognostic factor
Comparison
Outcome
Type of Question
Type of Study
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 69
Type of
Question
Type of
Study
70EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Type of questions:
Therapy determine the effect of an
assigned intervention
Does this treatment work?
Study
Design:
Systematic Review/Meta-Analysis
Randomized Controlled Trial
Cohort Study
71EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Type of questions:
Diagnosis Determine the ability of a test
to differentiate between those
with and without a target
condition
Is one test as good or better
than another test?
Study
Design:
Cross Sectional
Prospective comparison
Sensitivity and Specificity
72EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Type of questions:
Prognosis Determine a patient’s likely
clinical course over time due to
factors other than interventions
What will happen to these
patients over time?
Study
Design:
Cohort Study
73EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Type of questions:
Harm Determine the effects of
potentially harmful agents
Is this agent harmful?
Study
Design:
Cohort Study
Case-Control Study
*Randomized Controlled Trial
74EBP the Basics: Study Design and Randomized Controlled Trials. 2017
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nce
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76EBP the Basics: Study Design and Randomized Controlled Trials. 2017
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77EBP the Basics: Study Design and Randomized Controlled Trials. 2017
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nce
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78EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Know your chances. Steven
Woloshin et al. University of
California Press, 2008
79
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
ExerciseBuild-a-Study
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 82
Who is your population and how would you
select them?
Who is your comparison
group and how would you
select them?
What would you assess? What is the direction of
inquiry?
What are the Benefits and Problems?
83EBP the Basics: Study Design and Randomized Controlled Trials. 2017
EBP the Basics: Study Design and Randomized Controlled Trials. 2017 84
Study
Design
1. Describe the studies used in
clinical
medicine
2. Identify the strengths /
weaknesses
3. Identify search
strategies in
PubMed
4. Identify study designs
from article
abstracts
Publication Type
MeSH
◦ Case-Control Studies
◦ Cohort Studies
◦ Sensitivity and Specificity
◦ Qualitative Research
Clinical Queries
86EBP the Basics: Study Design and Randomized Controlled Trials. 2017
87
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
88EBP the Basics: Study Design and Randomized Controlled Trials. 2017
89EBP the Basics: Study Design and Randomized Controlled Trials. 2017
90
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
91EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Cross sectional
Prospective blind comparison
Sensitivity and Specificity[MeSH]
Best way to search:
Specificity[tiab] OR Sensitivity and Specificity[MeSH]
92EBP the Basics: Study Design and Randomized Controlled Trials. 2017
Therapy
Diagnosis
Harm/Etiology
Prognosis
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017 93
Can a Mediterranean-style diet reduce CV risk?
Your pediatric patient has abdominal pain. Should you use US or CT to rule out appendicitis?
Your new house is near power lines. Are you going to get leukemia?
Your patient suffered a TBI during a motorcycle crash and is in in a coma. When will he make a full recovery?
You know much has been written about ICDs for Afib and want to find something that synthesizes the evidence for you.
EBP the Basics: Study Design and Randomized Controlled Trials. 2017 99
Study
Design
1. Describe the studies used in
clinical
medicine
2. Identify the strengths/
weaknesses
3. Identify search
strategies in
PubMed
4. Identify study designs
from article
abstracts
NAME THAT STUDY
1. Randomized Controlled Trial
2. Cohort Study
3. Case Control Study
4. Case Series
5. Systematic Review
6. Cross-Sectional Study
1. Randomized Controlled Trial
2. Cohort Study
3. Case Control Study
4. Case Series
5. Systematic Review
6. Cross-Sectional Study
1. Randomized Controlled Trial
2. Cohort Study
3. Case Control Study
4. Case Series
5. Systematic Review
6. Cross-Sectional Study
Persistent hiccups have been reported to occur occasionally during
rehabilitation hospitalizations. Hiccups can interfere with patient
participation and progress, and this can lengthen and complicate the
rehabilitation hospitalization. Chlorpromazine, the only Food and Drug
Administration-approved agent specifically indicated for hiccups, is often
chosen as a first-line treatment. However, chlorpromazine does not always
provide favorable results. The intent of this paper is to (1) review hiccups
and implications of persistent hiccups in the rehabilitation setting, (2)
provide additional evidence that chlorpromazine is often not the best
treatment choice for hiccups in rehabilitative patients, (3) report the
effectiveness and favorable tolerability of modest doses of gabapentin in a
small ________ of three patients, and (4) review potentially effective
treatment approaches for hiccups.
1. Randomized Controlled Trial
2. Cohort Study
3. Case Control Study
4. Case Series
5. Systematic Review
6. Cross-Sectional Study
1. Randomized Controlled Trial
2. Cohort Study
3. Case Control Study
4. Case Series
5. Systematic Review
6. Cross-Sectional Study
1. Randomized Controlled Trial
2. Cohort Study
3. Case Control Study
4. Case Series
5. Systematic Review
6. Cross-Sectional Study
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
10
7
Study Design
should be part of
EBM search
strategy
Level of
evidence
matters
Study design
should
match
question
108
EBP the Basics: Study Design and
Randomized Controlled Trials. 2017
EBP the Basics: Study Design and Randomized Controlled Trials. 201710
9
Study
Design
1. Describe the studies used in
clinical
medicine
2. Identify the strengths /
weaknesses
3. Identify search
strategies in
PubMed
4. Identify study designs
from article
abstracts
Megan von Isenburg