Systematic Reviews of Randomised Controlled Trials

Question 1

What are the reasons for differences between RCT’s?

Answer 1

Differences:
- chance
- in people compared
- in care other than being investigated
- in the way treatment effects are assessed
- in follow-up
Available evidence
- difference in reporting
- biased selection

Question 2

What is publication bias?

What 2 forms of bias does it include?

Answer 2

When the publication of research results depends on their nature and direction

• positive results bias - when authors are more likely to submit, or editors to accept, positive than negative or inconclusive results
• outcome reporting bias - when several outcomes within a trial are measured but are reported selectively depending on the strength and and direction

Question 3

What are the benefits of reviews?

Answer 3

• volume of literature condensed
• new information made accessible
• some reviews are extremely good and have taken considerable time to find all the relevent information and review the topic well

Question 4

Define systematic review

Answer 4

the research method generally used to synthesise multiple pieces of research evidence on the effectiveness of a treatment

• clear question being addressed
• an explicit and detailed statement of the methods used
• comprehensive ascertainment of the literature relevant to the review question
• steps to reduce bias in the review process

Question 5

What are the stage in a systematic review?

Answer 5

define question
write protocol
search of evidence
elect relevant studies
appraise studies
extract, analyse and summarise data
interpret review results
discussion and conclusion

Question 6

What is a meta-analysis?

Answer 6

statistical technique used to combine the quantitative results from a number of studies

Question 7

What are the advantages of systematic reviews?

Answer 7

• can be the best source of evidenceon the effects and effectiveness of healthcare interventions
• assimilation of large amounts of research evidence
• provide reliable unbiased estimates of effect
• increase precision of estimates of effects
• provide information about the generalisability and consistency of effect
• identify what information is missing
• useful for making decisions

Question 8

What are three databases within the Cochrane library?

Answer 8

Cochrane database for systematic reviews
Database of abstracts of reviews of effects (DARE)
Health technology assessment