systematic review and meta-analysis

Question 1

what is the hierarchy of evidence?

Answer 1

Question 2

what is a review?

Answer 2

A ‘review’ is the generic term for any attempt to synthesise the results and conclusions of two or more publications on a given topic.

Question 3

what are the different types of reviews?

Answer 3

1) Traditional literature reviews/narrative reviews
2) Systematic reviews (with or without meta‐analysis/ meta-synthesis)

Question 4

why is a narrative reviw not sufficent?

Answer 4

– bias arising from the studies included in the review

– bias arising from the studies not included in the

review
– bias arising from the way the review is done.

E.g. just including the papers which support your existing view point and ignoring those which don’t.

Question 5

what is a systematic review?

Answer 5

• summary of medical literature
• uses explicit and reproduceible methods to systematically search, critically appraise and synthesize on a specific issue
• synthesises the results of multipple research studies
• reduces bias and random erors

Question 6

what are the aims of a systematic review?

Answer 6

– Systematic (e.g. in its identification of literature)

– Explicit (e.g. in its statement of objectives, materials and methods)

– Reproducible (e.g. in its methodology and conclusions)

Question 7

compare and contrast systematic vs narrative literaure reviews

Answer 7

Question 8

why are desicions about systematic reviews made at the outset?

Answer 8

So that retrospective decision-making does not bias findings

Question 9

where can you register your research protocol so that others dont do the same research as you?

Answer 9

PROSPERO

Question 10

What things should you think about when formulating the research question?

Answer 10

what method is used to evaluate

Question 11

what is the structural framework that is udsed to write a systemic review using qualatative studies and mixeed research?

Answer 11

Question 12

outline the step by step process of a systemic review

Answer 12

1. Well-formulated question
2. Comprehensive database search
3. Unbiased selection and abstraction process
4. Critical appraisal of selected studies
5. Synthesis of data and interpretation of results (evidence synthesis)

Question 13

what is an example of the application of SPIDER?

Answer 13

Question 14

what is inclusion criteria?

Answer 14

this is a criteria for the type of papers you wil be looking at and the criteria you have as a minum for inclusion into your review

Inclusion criteria – relate exactly to your PICO(ST)/ SPIDER criteria plus dates of studies and language of publication

Question 15

what is exclusion criteria?

Answer 15

Exclusion criteria – clearly delineate which studies will not or should not be included

Question 16

what is the benefit of having clear inclusion and exclusion criteria?

Answer 16

ensures that similar studies are being compared- so youre not comparing apples and oranges

Question 17

what is a good tool for appraising bias in RCTs?

Answer 17

Cochrane Risk of Bias tool / CONSORT

Question 18

what is a good tool for appraising observational studies?

Answer 18

STROBE

Question 19

what is the PRISMA statement?

Answer 19

this is a checklist of items that need to be reported in a systmaic review

Question 20

what are limitations of systematic reviews?

Answer 20

• There may be no trials/evidence

– If you apply all your criteria effectively and get <5 studies, this is fine!

• Lack of good quality evidence is a finding…

The trials may be of poor quality

Results may still be inconclusive

Practice does not change just because you have the evidence of effect/effectiveness

Question 21

define meta analysis

Answer 21

the statistical technique involved in extracting and combining quantitative data to produce a summary result.

Question 22

what is meta-synthesis?

Answer 22

efers to a group of methods used to synthesise qualitative (or mixed) data to produce a summary result/ a re-analysis of previous studies/study findings.

Question 23

strength of meta- analysis

Answer 23

Effect of an intervention is seen over a bigger sample size than possible in a single trial

• Results of each study are weighted for sample size
• Results from a range of settings can be compared
• Can evaluate homogeneity of results, i.e. variability of effect sizes
• Can explore variability, i.e. test moderators of effect size (e.g. study quality)

Question 24

what are weaknesses of meta-analysis?

Answer 24

Heterogeneity – studies which measure things differently are difficult to combine, orcombination becomes meaningless: “apples and oranges”

Publication bias – examine with funnel plot- this is when only papers with positive results are published so you dont get the full picture

Requires a lot of effort and subject-area expertise

Mechanics of statistics may obscure theory