Research methodology 6: Systematic Reviews Flashcards
What is the problem with the information explosion?
Too much information
• Poor quality research
• Insufficiently relevant to be clinically useful
• High quality information is often not easy to find
what is a review?
A ‘review’ is the generic term for any attempt to
synthesise the results and conclusions of two or more
publications on a given topic.
what are 2 types of reviews?
Traditional literature reviews/narrative reviews
2) Systematic reviews (with or without meta‐analysis/
meta-synthesis)
what is a narrative review?
Some reviews are usually based on narrative or
commentary and are produced by a ‘content
expert’
why are narrative reviews not sufficient?
– 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.
define systematic review
A systematic review is a summary of the medical
literature that uses explicit and reproducible
methods to systematically search, critically
appraise, and synthesize on a specific issue. It
synthesizes the results of multiple primary studies
related to each other by using strategies that
reduce biases and random errors
what are the aims of a systematic review
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)
Compare a narrative review and a systematic review
Scientific approach to a review article • Comprehensive search for relevant articles • Inclusion criteria determined at outset • Explicit methods of appraisal and synthesis • Reduce bias • Reproducible - reliable basis for decision-making • Resolve controversy between conflicting studies • Identify gaps in current research • Meta-analysis/meta-synthesis may be used to quant/qualitatively pool outcomes • Depend on authors’ inclination (bias) • Author can evolve criteria for inclusion • Search any databases • Methods not usually specified • Narrative summary • Not easily (/at all) replicable
define each letter of PICOST
Population (e.g. patients with asthma)
I An identified intervention (e.g. Meditation)
C An explicit comparison (e.g. Usual Care)
O Relevant outcomes (e.g. Quality of Life)
(S) Setting
(T) Timing e.g. of follow up
if there is no comparison group, what can you use?
SPIDER Sample Phenomenon of interest Design Evaluation Research type
what are tools for appraising the study
CONSORT
STROBE
what does it mean to critically appraise?
Appraise studies against your chosen tool/s
• Every study gets a score
• Accept or reject study depending on prechosen threshold
what is evidence synthesis ?
Findings from the individual studies aggregated to
produce a ‘bottom line’
what are some limitations of SR?
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
what is a meta analysis ?
A meta‐analysis is the statistical
combination of at least 2 studies to produce
a single estimate of the effect of the health
care intervention under consideration.
