Population Science Flashcards

(28 cards)

1
Q

is the 95% confidence interval includes the number 1 what does this mean about the results?

A

they are not statistically significant. The null hypotheses is rejected.

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2
Q

what is blinding

A

where the patient is not aware of which treatment they are being given

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3
Q

what are the advantages of blinding

A

minimises allocation bias, behaviour changes of the patient, measurement bias

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4
Q

what is measurement bias

A

how assessors may later the way they collect information

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5
Q

what are appropriate losses to follow up

A

where the patient has to be removed from the trial due to a deterioration in their health

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6
Q

what are unfortunate losses to follow up

A

where a patient chooses to withdraw from the trial

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7
Q

why may patients not be compliant with their treatment

A

didn’t understand instructions
feel better already
don’t like the treatment

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8
Q

how can you improve patient compliance

A

explain instructions fully

directly observed treatment

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9
Q

what is As-Treated analysis

A

where you only analyse the results from those how fully complied with treatment and discard follow up losses

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10
Q

what is Intention-to-treat analysis

A

where the analysis of the trial is done according to original allocation regardless of follow up losses and compliance

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11
Q

True or False: As-treated analysis gives a more realistic size of the effect of the treatment

A

false - its intention-to-treat analysis

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12
Q

why are RCTs used

A

they remove confounding and allocation bias

whilst also allowing for reproducible, controlled and fair trials

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13
Q

what are RCTs

A

where 2 identical groups are produced to make a fair comparison when looking at 2 different treatment options

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14
Q

what is a primary outcome measure

A

the main and preferably only outcome

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15
Q

what is a secondary outcome measure

A

other outcomes of interest

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16
Q

what is the placebo effect

A

where patient attitude to their illness or the illness itself may be improved if the patient feels that something is being done about it

17
Q

what is used to remove the placebo effect

18
Q

what is a placebo

A

an inert substance made to appear identical to a treatment

19
Q

What are systematic reviews

A

Where lots of similar studies answering the same question are brought together

20
Q

What is meta-analysis

A

Where the studies in a systematic review are pooled together to get one overall result

21
Q

What is the purpose of meta-analysis

A

Collecting the study results means you can make more certain statements about the information as it based on a larger group.
Also reduces problems in interpreting the data

22
Q

How is meta-analysis presented

A

On a Forrest plot

23
Q

How are studies on a Forrest plot weighted

A

Those with more certainty (smaller CIs) and a bigger study size are weighted more heavily

24
Q

What is the random effect model

A

A difference in a Forrest plot taking into account variation between studies

25
How do you interpret Forrest plots
Boxes = odds ratio Horizontal lines = CI of the study Diamond = odds ratio of pooled estimate and its width is the CI
26
What can be used to explain variation between studies
Sub group analysis - this looks at the study characteristics and the patient profiles
27
What is publication bias
Where studies which are statistically significant are more likely to be published than those which aren’t
28
What plot is used to determine if publication bias is present
A funnel plot