Critical Appraisal - Systematic Reviews & Meta-Analysis Flashcards Preview

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Flashcards in Critical Appraisal - Systematic Reviews & Meta-Analysis Deck (18)
1

What is a systematic review?

A literature review focused on a single question with well defined criteria for review. It is the highest level of evidence.

2

What is a meta-analysis?

The statistical analysis aspect of systematic review - analyses combined data from multiple studies. Done using statistical software.

3

What are the purposes of a meta-analysis?

Increase power, resolve uncertainty, improve estimates, answer other questions (such as secondary outcomes)

4

What are the inclusion and exclusion criteria used to select studies for a systematic review?

The PICOT parameters plus other relevant criteria such as sample size

5

How might bias be introduced when selecting studies?

By selecting only studies which are in English, or by selecting only studies which have been published

6

What is the CONSORT checklist?

A checklist of items that should be included in a randomised trial

7

What is the Cochrane guidelines?

A guide which looks at various types of bias to judge whether or not the individual study accounted for it

8

What are the key statistical issues in a meta-analysis?

outcome, weighting and heterogeneity

9

What does the outcome look at?

The average of each of the studies - such as the relative risk. Can be either a relative or absolute measure.

10

What determines the weighting of each study?

The number of outcomes - which is usually an indirect measure of the sample size

11

Why is heterogeneity important?

Because only studies which are not heterogenous should be combined

12

How is the information presented in a meta-anaysis?

In a forest plot

13

What does the vertical line in the forest plot represent?

The line of null effect

14

What does the size of the square in the forest plot represent?

The size of each of the studies

15

What does the horizontal line in the forest plot represent?

The confidence interval

16

What does the diamond in the forest plot represent?

The pooled result of all the studies - the vertical line of the diamond shows the point estimate and the horizontal width of the diamond shows the confidence interval

17

How is statistical heterogeneity determined?

Using a p value. If the p value is greater than 0.05 then the studies are not heterogenous so can be combined.

18

How else is heterogeneity determined?

Subjectively in terms of the PICOT parameters