Systematic Reviews and Meta analysis

Question 1

what’s the difference between a systematic review and a meta analysis?

Answer 1

systematic review = process of gathering, combining and interpreting the results of research into a particular question

meta analysis is the statistical methods that go into combining te information from different studies

Question 2

why are meta analysis important?

Answer 2

becasue they compile data and save time/money - if the first 6 trials of a drug show that it’s inneffective, then you don’t need to carry out the 7th trial, nor should it be approved

They allow us to take many small trials and compile it with larger studies to give us a full picture

Question 3

what is the I^2 statistic?

Answer 3

it tells us what percentage of the variation between studies is attributable to heterogeneity

if the I^2 statistic is >60%, it is usually taken as a random result, rather than fixed

Question 4

what are the drawbacks of systematic reviews?

Answer 4

they are only as good as the data available to them -

• there is considerable evidence that data is withheld and selectively published by pharmaceutical companies

inclusion/exclusion criteria are poorly described making trials seem more widely applicable than they really are