EBM Flashcards

1
Q

EBM is

A

The application of the best available, clinically relevant research to clinical care, involves integration of evidence with clinical expertise and patient values

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2
Q

EBM in practice means

A

Asking relevant questions to identify what is important from all available info

Looking for evidence that is peer reviewed, research studies with rigorous collecting methods and analysed data

Interpreting evidence by critically evaluating, considering biases and stats, whether relevant

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3
Q

What is a case report, when helpful

A

A retrospective report on a single pt
Used for special interest cases on things not commonly encountered

Helpful if have unusual case and see someone has done a case report on similar as can contact to improve your care

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4
Q

What is a case series

A

Collection of case reports that are similar and published together
Often same disease outcome or treatment
Focus on the specific cases not general trend

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5
Q

What is an ecological study

A

Retrospective
Uses population data that is already available to investigate overall trends and associations within large groups of people- ie city, factory, big GP
Generally looks at exposure and outcome

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6
Q

Pros and cons ecological study

A

Pros: data already available so rapid and cheap and large scale

Cons: doesn’t control for confounding variables relevant to exposure/outcome

Those with outcome may not have been those exposed

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7
Q

What is a cross sectional survey

A

For exposure and outcome prevalence at a single time point of a particular defined population
Retrospective
Uses a questionnaire that may be filled by a survey/interview/by the dr not pt

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8
Q

Cons of a cross sectional survey

A

Inaccurate recall

Wish to please investigator so unreliable

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9
Q

What is a case control study

A

Identifies risk factors, NOT effectiveness if treatment
Retrospective
Looks for possible risk factors in the history of a case group not present in the control group
Take history from both case and control groups, compare and conclude whether something likely a risk factor

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10
Q

Cons of a case control study

A

Doesn’t account for confounding variables, other differences may explain outcome
Can try to match controls to cases but difficult to include all confounders

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11
Q

what is a cohort investigation

A

follows a group or population (the cohort) over time (decades/years)
may compare groups or just follow 1
observational, no intervention
usually large scale
ie follow smokers and non smokers over time to see outcome
prospective

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12
Q

pros and cons cohort investigation

A

allows to study things would be unethical to manipulate ie exposing to dangerous things

confounding variables may explain outcome though statistics can help

people may leave the study as is long

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13
Q

randomised control trial

A

gold standard of clinical research
prospective
used for evaluating effectiveness of treatment
large numbers, random selection obviates confounders and bias, high validity

pts with similar characteristics randomly assigned to control or treatment group, follow up, compare results. control group gets placebo, used to show significance of treatment

can’t use to study risk factors as unethical to expose

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14
Q

cross over trial

A

type of randomised control trial comparing 2 or more treatments

each pt receives 2 or more treatments
tA, washout,tB
tB, washout, tA
pt randomly allocated to 1 or other treatment, follow by washout period, follow by next treatment

order of treatment may influence results
higher burden on pt so less compliance more likely to leave study
long lasting interventions unsuitable

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15
Q

systematic review

A

extensive critical analysis of all relevant publications
uses a framework and clear criteria for inclusion and exclusion
precise search term
methods section

takes a long time so may miss new stuff

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16
Q

meta analysis

A

technique for combing data from multiple studies
clear statistical analysis of pooled data
more powerful than its constituent investigations

looks at similar studies and analyses data for a statistically significant result

17
Q

what are the retrospective study methods

A

case report/series
ecological study
cross sectional surgery
case control

18
Q

what are the prospective study methods

A

cohort investigation
randomised control trial
cross over trial

19
Q

what is the heirachy of evidence

A
  1. systematic reviews and meta-analysis
  2. randomised control trial
  3. cohort study
  4. case-control trial
  5. cross-sectional study
  6. ecological study
  7. case series and report
  8. ideas, editorials, opinions
20
Q

what type of study is best for investigating risk factors

A

case control

21
Q

what type of study is best to test a treatment’s effectiveness

A

randomised control trial

22
Q

what type of study is best for a single time point of a defined population

A

cross sectional study

23
Q

what type of study is best for following a group over time

A

cohort investigation study

24
Q

what type of study is best for looking at exposure and outcome in large groups of people

A

ecological study

25
Q

define validity

A

accuracy

validity is the extent something accurately measures what it should, the extent findings reflect the truth

26
Q

define reliability

A

consistency

degree of stability shown when measurement repeated under identical conditions

27
Q

define bias

A

when systematic error is introduced by selecting/encouraging one outcome above others
any deviation from the truth

28
Q

define confounding variable

A

a third variable that influences both the dependent and independent variables

29
Q

define independent variable

A

the variable that is manipulated by the researcher to cause a change in the dependent variable

30
Q

define dependent variable

A

is affected by a change in the independent variable

31
Q

give example of personal factors that influence how people perceive risk

A

emotional state
previous experience
education level

32
Q

give example of contextual factor that influences how people perceive risk

A

how the risk is communicated

33
Q

define relative risk, give example

A

relative likelihood of outcome in people exposed vs not exposed to risk factor

ie relative risk of thromboembolism if taking pill vs not taking pill is doubled, but reality is

if take pill= 2/7000
if don’t take pill= 1/7000

34
Q

define absolute risk, given example

A

absolute risk is the risk of developing a condition over a certain time period

ie risk of thromboembolism if taking pill 2/7000, if not taking pill is 1/7000

change in relative risk is 1/7000

35
Q

identify which of these is the absolute or relative risk
risk of eating a bacon sandwich daily increases risk of bowel cancer

there is an 18% increase in risk
it goes from 6% to 7%

A

18% increase in relative risk

absolute risk goes from 6 to 7%

36
Q

which type of risk should not be used by itself

A

relative risk should not be used by itself

37
Q

what are confidence intervals

A

margin of error, presented alongside risk info

often expressed as % where a population mean lies between upper and lower interval