1. What is a review?
An article which looks at a question or subject and seeks to summarise and bring together evidence on a health topic.
Ask What is a review?
Ask for examples
update
prescribers journal
drug and therapeutic journal
bmj
medical textbooks
medicine

2. Objectives of session Know what is special about a systematic review
know what meta-analysis is
have a check list for looking at systematic reviews
first slide

3. What is a systematic review?
In a review a question must be posed, a target population of information sources identified and accessed, appropriate information obtained from that population in an unbiased fashion, and conclusions derived.
the methodology will be explicit and reproducible.
Ask what is a systematic review
emphasise that it is a piece of rigorous research
with all of the steps involved in primary research.
IT IS REPRODUCIBLE
Perhaps draw attention to the otitis media meta analysis and the explicit steps taken to ensure all trials were found and the the trials were graded blind to the author and to the journal in which they were published

4. check list of data sources
medline
cochrane
other medical and paramedical databases
foreign language literature
Grey literature.(theses, internal reports, non-peer reviewed journals, pharmaceutical industry files
references
other unpublished sources
raw data from published trials
flip chart - derive list
talk about publication bias
Negative results

5. Why bother with systematic reviews?
To reduce large volumes of information to bite size pieces.
To allow decision makers to integrate critical pieces of biomedical information.
An efficient scientific technique which is often less costly than embarking on new research.
The generalisability of scientific findings can be established.
Look at the Thrombolysis meta analysis
Look at how early the benefits of thrombolysis were obvious
To attempt to eliminate reviewer bias:
1987(second edition Oxford Textbook of medicine) A distinguished cardiologist advised….”The clinical benefits of thrombolysis (in treating patients with MI) whether expressed as improved patient survival or preservation of left ventricular function, remain to be established.” This appeared 4 years after a review by Yusuf showed the clear benefits of thrombolysis.
Maybe look at the lignocaine review

6. Why bother with systematic reviews?
To assess the consistency of relationships.
To explain data inconsistencies and conflicts in data.
Increased power.
Increased precision in estimates of effect.
To reduce random and systematic errors.
In the thrombolysis meta analysis Iv streptokinase could have been shown to be life saving 20 years ago
ISIS2
GISSI
no change in evidence of efficacy but slightly narrowed the confidence intervals. more than patients in each trial.

7. What on earth is Meta-analysis?
A systematic review where there is statistical analysis of data from the trials included in the review.

8. What can go wrong with a systematic review?
Problem formulation
Is the question clearly focused?
Study identification
Is the search for relevant studies thorough?
Study selection
Are the inclusion criteria appropriate?
Publication bias

9. What can go wrong with a systematic review?
Appraisal of studies
Is the validity of included studies adequately assessed?
Data collection
Is missing information obtained from investigators?
Data synthesis
How sensitive are the results to changes in the way the review is done?
Blind assessment of studies
Ask how sensitive the results are to changes in the way that the review is done.
Test how robust the results of the review are.
change inclusion criteria
include or exclude trials with some ambiguity as to whether they meet the inclusion criteria
Exclude unpublished studies
exclude studies of lower methodological quality
Reanalyse the data using different statistical approaches

10. What can go wrong with a systematic review?
Interpretation of results
Do the conclusions flow from the evidence that is reviewed?
Are recommendations linked to the strength of the evidence?
Are judgements about preferences (values attached to different outcomes) explicit?
If there is "no evidence of effect" is caution taken not to interpret this as "evidence of no effect"?
Are subgroup analyses interpreted cautiously?
conclusions do not exceed the evidence
Look at levels of evidence:
Health care interventions involve costs and risk of harm as well as expectations of benefit
practice recommendations require judgements about preferences (the values attached to different outcomes)
If conclusions involve such judgements this should be clearly stated.
e.g. HRT

11. Levels of evidence for treatment
Level I The lower limit of the confidence interval for the effect of treatment from a systematic review of randomised controlled trials exceeded the clinically significant benefit.
Level II The lower limit of the confidence interval for the effect of treatment from a systematic review of randomised controlled trials fell below the clinically significant benefit (but the point estimate of its effect was at or above the clinically significant benefit)
Level III Non-randomised concurrent cohort studies
Level IV Non-randomised historical cohort studies
Level V Case series

12. The Hierarchy of Evidence
Systematic reviews and meta-analyses
Randomised controlled trials with definite results
Randomised controlled trials with non-definite results
Cohort Studies
Case control studies
Cross sectional surveys
Case reports