1991 2015 3 1 picture 2 formulas amp 3 acronyms GATE Graphic Appraisal Tool for Epidemiology Graphic Architectural Tool for Epidemiology Graphic Approach To Epidemiology ID: 815164
Download The PPT/PDF document "2 GATE: Graphic Appraisal Tool for Epide..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Slide22
Slide3GATE:
Graphic Appraisal Tool for Epidemiology
1991 - 2015
3
1 picture, 2 formulas & 3 acronyms
Slide4GATE:
Graphic Appraisal Tool for
Epidemiology
Graphic
Architectural Tool
for
Epidemiology
Graphic
Approach To Epidemiology
making epidemiology accessible
4
Slide54
th
year medical students 1991
Slide6Jerry Morris
n
umerator denominator
epidemiology =
In: Uses of Epidemiology 1977
6
Slide7Slide8p
resentation outline
GATE is a framework for:
study design
study analysis
study error
practicing EBM
8
1 picture, 2 formulas & 3 acronyms
Slide91
Slide10GATE: a framework for study design
1 picture
10
every epidemiological
study can be hung on the GATE frame
1
picture
, 2 formulas & 3 acronyms
Slide11cohort
of British doctors
non-smokers
smokers
lung cancer events counted
yes
no
followed
for 10 years
smoking status allocated by measurement
(
observation)
cohort
/
longitudinal
/
follow-up study
11
1
picture: GATE frame
1
picture
, 2 formulas & 3 acronyms
Slide12British doctors
placebo
aspirin
MI
yes
no
5 years
r
andomly allocated to aspirin or placebo
12
1
st
acronym: PECOT
Participants
Comparison
Exposure
Outcomes
Time
P
E
C
O
T
r
andomised controlled trial
1 picture, 2 formulas & 3
acronyms
Slide13m
iddle-aged Americans
‘normal’ weight
overweight
d
iabetes status measured in all participants
yes
no
b
ody mass index measured
c
ross-sectional (prevalence) study
13
P
E
C
O
T
Slide14m
iddle-aged American women
b
reast cancer
m
ammogram negative
yes
no
receive mammogram screening test
d
iagnostic
test (prediction) study
m
ammogram positive
14
P
E
C
O
T
Slide15m
iddle-aged American women
m
ammogram
test
no breast cancer
positive
negative
Gold Standard
d
iagnostic (test accuracy) study
b
reast cancer
15
P
E
C
O
T
Slide16non-smokers
smokers
l
ung cancer
yes
no
smoking status measured
c
ase-control study
16
P
E
C
O
T
cases
controls
(all nested in virtual cohort studies)
Slide17£100
Slide182
Slide19GATE: a framework for study analysis:
1
st
formula: occurrence = outcomes ÷ population
19
the numbers in epidemiological studies can be hung on the GATE frame
1 picture, 2
formulas
& 3 acronyms
Slide20British doctors
non-smokers
smokers
Lung cancer
yes
no
10 years
smoking status measured
20
1
st
formula
: occurrence of outcomes =
n
umber of outcomes ÷ number in population/group
Participant Population
Comparison Group
Exposure Group
Outcomes
Time
P
EG
CG
O
T
a
b
Slide21British doctors
non-smokers
smokers
Lung cancer
yes
no
10 years
smoking status measured
21
Population
Comparison Group
Exposure Group
Outcomes
Time
P
EG
CG
O
T
Exposure Group Occurrence (EGO) = a
÷
EG
= number of outcomes (a) ÷ number in exposed population (EG)
a
b
Slide22British doctors
placebo
aspirin
MI
yes
no
5
years
r
andomly allocated
22
Population
Comparison Group
Exposure Group
Outcomes
Time
P
EG
CG
O
T
a
b
Comparison Group Occurrence (CGO) = b
÷
CG
= number of outcomes (
b
) ÷ number in comparison population (CG)
Slide23yes
no
23
E
pidemiology =
N
umerator ÷
D
enominator
Participant Population
Comparison Group
Exposure Group
Outcomes
Time
P
EG
D
O
T
a
N
m
iddle-aged American women
b
reast cancer
m
ammogram negative
receive mammogram screening test
m
ammogram positive
Slide24British doctors
non-smokers
smokers
Lung cancer
yes
no
10 years
smoking status measured
24
t
he goal of all epidemiological studies is to calculate
EGO and CGO
P
EG
CG
O
T
a
b
EGO:
Occurrence (risk) of cancer in smokers
C
GO:
Occurrence of cancer in non-smokers
Slide25Middle-aged Americans
Low BMI
High BMI
EGO:
Average blood glucose in EG
high
low
Body Mass Index (BMI) measured
25
P
EG
CG
O
C
GO:
Average blood glucose in CG
Slide26Middle-aged Americans
Low BMI
High BMI
b
lood glucose
high
low
Body Mass Index (BMI) measured
c
ross-sectional study with numerical measures
26
P
E
C
O
T
Slide27Middle-aged American women
mammogram
no Breast cancer
positive
negative
Gold Standard
Breast cancer
27
P
E
C
O
T
EGO:
likelihood of a positive mammogram if breast cancer
C
GO:
likelihood of a positive mammogram if no breast cancer
Slide28EGO ÷ CGO
= Relative
Risk (RR
)
EGO – CGO
= Risk Difference
(RD)
i
ts all about EGO and CGO
measures of occurrence
: risk; rate; likelihood; probability; average; incidence; prevalence
28
1
st
formula:
occurrence
= outcomes ÷ population
Slide293
Slide30GATE: framework
for
nonrandom error
2
nd
acronym: RAMBOMAN
30
R
ecruitment
A
llocation
M
aintenance
B
lind
O
bjective
M
easurements
AN
alyses
1 picture, 2 formulas & 3
acronyms
Slide31R
AMBOMAN
Recruitment of participants
‘who
are the findings
applicable to?’
P
P
Study setting
Eligible population
31
r
ecruitment process
Slide32EG CG
O
T
RCT: a
llocated by
randomisation
(
e.g
to drugs
)
EG CG
O
T
Cohort: a
llocated
by measurement
(e.g. smoking)
R
A
MBOMAN:
‘
were participants well
Allocated
to exposure & comparison groups?’
EG & CG similar at baseline?
w
as
Allocation
to EG & CG successful?
32
E & C measures accurate?
Slide33RA
M
BOMAN
EG CG
O
T
‘were Participants well
Maintained
in the groups they were allocated to?’
P
completeness
of follow-up
c
ompliance
c
ontamination
c
o
-
interventions
33
Slide34RAM
B
O
M
AN
EG
CG
O
T
‘were
outcomes
well
Measured
?’
w
ere they measured
Blind
to whether participant was in EG or CG
?
P
34
Slide35RAMB
OM
AN
EG
CG
O
T
‘were
outcomes
well
Measured
?’
w
ere they measured
Objectively
?
P
35
Slide36RAMBOM
AN
EG
C
CG
C
O
T
P
36
EG
A
CG
A
a
b
‘were the
ANalyses
done well
?’
If RCT were
I
ntention
T
o
T
reat (ITT)
analyses done?
Slide37RAMBOM
AN
EG CG
O
T
‘were the
ANalyses
done well
?’
P
a
djustment for baseline differences / confounding?
37
Slide38GATE
:
random error:
2
nd
formula:
random error = 95% confidence interval
38
There is about a 95% chance that the true
value in
the underlying
population
lies
within
the 95% CI (assuming no non-random error)
EGO ± 95% CI
C
GO ± 95% CI
1 picture, 2
formulas
& 3 acronyms
s
ample from a population
Slide39GATE
:
a framework for error in systematic reviews & meta-analyses:
3
rd
acronym: FAITH
1 picture, 2 formulas & 3
acronyms
39
Slide40study sources
s
tudies appraised & allocated:
included
excluded
s
tudies summarised
& pooled if homogeneous
systematic review: a study
of studies
studies
screened
40
Slide41study sources
s
tudies appraised & allocated:
included
excluded
s
tudies summarised
& pooled if homogeneous
studies
screened
critical appraisal of SR:
FAITH
Find
Appraise
Include
Total
H
eterogeneity?
1 picture, 2
formulas
& 3 acronyms
41
Slide424
Slide43GATE: framework for the 4 steps of EBP
43
Slide44t
he steps of EBP:
A
sk
Acquire
3. Appraise
4. Apply & Act
44
Slide45yes
no
45
1. Participants
3. Comparison
2. Exposure
4. Outcomes
5. Time
P
E
C
O
T
EBP Step 1:
ASK
- turn your question into
a focused 5-part PECOT question
Slide46EBP Step
2:
ACQUIRE
the evidence – use
PE
COT
to help choose search terms
46
yes
no
Participants
Comparison
Exposure
Outcomes
Time
P
E
C
O
T
Slide47P
E
C
O
T
P
E
C
O
T
R
ecruitment
A
llocation
M
aintenance
b
lind
o
bjective
M
easurements
AN
alyses
47
EBP Step 3:
APPRAISE
the evidence – with the picture, acronyms & formulas
Occurrence = outcomes ÷ population
Random error = 95% Confidence Interval
Slide48APPLY
the evidence by AMALGAMATING the
relevant information &
making
an
evidence-based decision:’
the X-factor
©
48
Slide4949
Slide50e
pidemiological evidence
p
atient’s clinical circumstances
s
ystem features
v
alues & preferences
X-factor: making evidence-based decisions
Practitioner
e
X
pertise
: ‘putting it all together’
- the
art of practice
e
conomic
legal
political
person
family
community
practitioner
social
p
hysical health
psychological
Clinical expertise in the era of evidence-based medicine and patient choice. EBM 2002;736-8 (March/April)
50
Slide51GATE critically appraised topic (CATs) forms
Slide52GATE CAT –
4-
sheet workbook (in Excel)
sheet 1: GATE-Ask &
Acquire
52
Slide5353
GATE CAT – 3-sheet workbook (in Excel)
sheet 2: GATE-Appraise
(with calculator)
Slide5454
GATE CAT – 3-sheet workbook (in Excel)
sheet 3: GATE-Apply
Slide55Slide56Slide5757