PHTY211 Lecture Notes - Lecture 8: Childhood Obesity, Summary Statistics, Embase
Appraising a systematic review
• Describe what is meant by the term search strategy.
• Explain why it is important to
o Define the scope of a review,
o Have a comprehensive search strategy and
o Review the quality of included studies
• Critically appraise a systematic review
• What is a systematic review
o I a S‘ all aailale pulished ad upulished ‘CTs are reieed ad if they eet the
ilusio riteria the trials are sythesized ad the fidigs of the re‐aalysis of data are
presented.
o Provide a high level of evidence on the effectiveness of healthcare interventions
o Meta-analysis (MA)
• A eta‐aalysis is a type of S‘ i hih the data fro the studies that eet strit
inclusion criteria is combined and statistical analysis is repeated.
• Consists of 2 steps
▪ Extracting the size (and precision) of Rx effect from each study
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▪ Pooling the data to obtain an average single estimate based on all studies;
also includes the weighting of results from each study
• An advantage of pooling results from a number of studies is that the sample size is
increased and as a result so is the statistical power.
• EBP - clinical steps
o Formulate a clinical question
• Just like an RCT, prognostic and diagnostic studies a systematic review should
address a question
• PICO
o Search the literature for relevant evidence, Evaluate or critically appraise the evidence
for its validity and utility
• Sources of research evidence
▪ Joanna Briggs Institute
http://connect.jbiconnectplus.org/Appraise.aspx
▪ PEDro
▪ http://www.pedro.org.au/
▪ Cochrane Library (systematic reviews)
▪ http://.ohrae.org/ohrae‐reies
• "Every day someone, somewhere searches The Cochrane Library every
second, reads an abstract every two seconds and downloads a fulltext
article every three seconds."
• Are the results of the study valid?
▪ Was it clear which trials were to be reviewed?
• Which trials to be reviewed?
• Search strategy
• Clearly defined scope of review prior to undertaking a
search of relevant trials
• Clear criteria for inclusion and exclusion
• PICO
• Cochrane search strategy
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD00187
1.pub3/pdf
• Clearly defined scope of the review
• This review primarily aims to update the previous Cochrane
review of childhood obesity prevention research and determine
the effectiveness of evaluated interventions intended to
prevent obesity in children, assessed by change in Body Mass
Index (BMI).
• Secondary aims were to examine the characteristics of the
pogas ad stategies to aswe the uestios What woks
for whom, why ad fo what cost?
• Clear criteria for inclusion and exclusion
• Types of studies
• Types of participants
• Types of interventions
• Outcome measures
• Primary
• Secondary
▪ Were most relevant studies reviewed?
• Important to identify most relevant trials
• Conclude there is less evidence than really is
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Document Summary
Just like an rct, prognostic and diagnostic studies a systematic review should address a question: pico, search the literature for relevant evidence, evaluate or critically appraise the evidence for its validity and utility. Joanna briggs institute http://connect. jbiconnectplus. org/appraise. aspx: pedro, http://www. pedro. org. au, cochrane library (systematic reviews, http://(cid:449)(cid:449)(cid:449). (cid:272)o(cid:272)hra(cid:374)e. org/(cid:272)o(cid:272)hra(cid:374)e re(cid:448)ie(cid:449)s. Search strategy: clearly defined scope of review prior to undertaking a search of relevant trials, clear criteria for inclusion and exclusion, pico, cochrane search strategy http://onlinelibrary. wiley. com/doi/10. 1002/14651858. cd00187. Important to identify most relevant trials: conclude there is less evidence than really is. Systematically different conclusions from those included in review: publication bias. Language bias: grey literature, physiotherapy trials, medline, embase, cinahl, amed, psycinfo, cochrane, pedro, recency of review, new trials being published all the time. Formal assessment of quality after trials are included and prior to data extraction: usually carried out by 2 independent reviewers, methods to assess trial quality. Jadad s(cid:272)ale (cid:272)he(cid:272)klist: cochrane collaboration grade, risk of bias, consistency of effect, publication bias.
