Cochrane Collaboration Tool for Assessing Risk of Bias in Intervention Trials
Network Meta-analysis By: Dr. Lisa Calder December 2014
Network meta-analyses should not be viewed as the same as other meta-analyses. This specialized methodology is designed to answer complex management questions when there are multiple options possible. This is particularly helpful when a head-to-head RCT is not practical to conduct. The key requirement is that the studies being compared have at least one common or equivalent therapy among
PICOS Format By Dr. Lisa Calder March 2013
When reviewing systematic literature reviews, pay attention to how the research question is phrased. High quality studies will follow the PRISMA guidelines’ suggestion to use the PICOS (participants, interventions, comparisons, outcomes, study design) format. A precise research question will guide study selection and should also dictate how table 1 summarizes the included studies. Having these details will also assist the reader in evaluating the included studies for generalizability and clinical heterogeneity.
In a meta-analysis, researchers assess heterogeneity across studies, examine subgroups of studies to determine if selected subsets of the research data provide similar or different results, and calculate summary relative risk estimates. A pooled analysis is similar to a traditional meta-analysis, except that data are combined (or pooled) from multiple studies and are analyzed as a single dataset. If the data and methods are consider homogeneous across studies and the data are available, then a pooled analysis is a very legitimate approach.
The PRISMA statement (revised 2009 to replace QUORUM ) was developed by an international group to establish preferred reporting guidelines for systematic reviews and meta-analyses. David Moher of the Ottawa Hospital Research Institute is the lead author on the paper that includes the PRISMA 27-item checklist and four-phase flow diagram.
Even when individual studies included in best evidence summaries have a low risk of bias, publication bias can result in substantial overestimates of effect. Authors should suspect publication bias when available evidence comes from a number of small studies, most of which have been commercially funded. A number of approaches based on examination of the pattern of data are available to help assess publication bias. The most popular of these is the funnel plot; all, however, have substantial limitations. The likelihood of publication bias is less for studies that are not evaluating new drugs or devices.
QUOROM statement By: Dr. Lisa Calder December 2012
When critically appraising systematic literature reviews and meta-analyses, the reader will find the QUOROM statement to be a helpful tool. This guide helps you assess adequacy of search strategy, article selection and quality assessment. Furthermore, it provides the key elements which should be reported to allow you to assess the overall validity of the results. This reporting template also assists authors of SLR and MA to both design and write-up their studies in a rigorous way.
Reporting Standards for Systematic Reviews By Dr. Ian Stiell February 2013
The PRISMA statement () was developed to establish preferred reporting guidelines for systematic reviews and meta-analyses and includes a 27-item checklist and four-phase flow diagram. Observational studies are considered a lower level of evidence for interventions and have had two sets of guidelines developed: MOOSE (Meta-analysis Of Observational Studies in Epidemiology) and STROBE (STrengthening the Reporting of OBservational studies in Epidemiology).
Subgroup analyses in Meta-analysis By Dr. Lisa Calder May 2013
To avoid the biases of an unsystematic review (i.e. review article), a systematic review incorporates explicit inclusion and exclusion criteria, a comprehensive search for the evidence, and a summary of the results according to explicit rules. When a systematic review pools data across studies to provide a quantitative estimate of the treatment effect, this is called a meta-analysis. When the data cannot be pooled, the systematic review will provide a narrative synthesis of the evidence.
To Pool or Not to Pool By: Dr. Lisa Calder October 2014
Verification Bias By: Dr. Lisa Calder October 2014