research techniques made simple: the role of systematic reviews and meta-analysis in dermatology...
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![Page 1: Research Techniques Made Simple: The Role of Systematic Reviews and Meta-Analysis in Dermatology Katrina Abuabara, MD, MA 1 Esther E Freeman MD, PhD 2](https://reader033.vdocuments.net/reader033/viewer/2022061306/551470dd550346494e8b6052/html5/thumbnails/1.jpg)
Research Techniques Made Simple: The Role of Systematic Reviews and
Meta-Analysis in Dermatology
Katrina Abuabara, MD, MA1 Esther E Freeman MD, PhD2; Robert Dellavalle, MD, PhD, MSPH3
Affiliations: 1Department of Dermatology, University of Pennsylvania; 2Department of Dermatology, Harvard
Combined Dermatology Residency Program, Massachusetts General Hospital; 3Dermatology Service, Denver VA Medical
Center
![Page 2: Research Techniques Made Simple: The Role of Systematic Reviews and Meta-Analysis in Dermatology Katrina Abuabara, MD, MA 1 Esther E Freeman MD, PhD 2](https://reader033.vdocuments.net/reader033/viewer/2022061306/551470dd550346494e8b6052/html5/thumbnails/2.jpg)
Summary Points
• A systematic review is a comprehensive summary of available data pertaining to a specific question, organized through a rigorous design. Systematic reviews often contain a meta-analysis, which is a statistical method for synthesizing data from multiple studies.
• These techniques are used to answer specific research questions and may minimize bias, improve precision of intervention estimates, and increase the statistical power of identifying a real effect. They can also help to settle controversy when individual studies show conflicting results, and they may identify research gaps.
![Page 3: Research Techniques Made Simple: The Role of Systematic Reviews and Meta-Analysis in Dermatology Katrina Abuabara, MD, MA 1 Esther E Freeman MD, PhD 2](https://reader033.vdocuments.net/reader033/viewer/2022061306/551470dd550346494e8b6052/html5/thumbnails/3.jpg)
Study design methodology• The PRISMA (Preferred Reporting Items for
Systematic reviews and Meta-Analyses) Statement describes criteria for developing, carrying out, and evaluating these types of studies.
• Formulating an appropriate and specific research question is critical.
• Eligibility criteria should be prespecified and a search strategy for included studies should be comprehensive and clearly described; these are often presented in a flow diagram.
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Example of a Flow Diagram
*Originally published with the PRISMA Statement (Liberati A, Altman DG, Tetzlaff J, et al. (2009) PLoS Medicine 6:e1000100)
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Assessing Risk of Bias in Individual Studies
• A descriptive approach of assessed methodological components such as selection bias, performance bias, detection bias, attrition bias, and reporting bias is recommended.
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Statistical Meta-analysis
• Meta-analysis allows data from multiple studies to be statistically combined.
• First, a summary statistic is calculated for each study.
• Next, an overall intervention effect estimate is calculated.
• Finally, to ensure that the results are valid and robust, researchers typically test for heterogeneity and publication bias and perform sensitivity analyses.
• Results are often presented in a forest plot.
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Forest Plot
• Used to present the results of a meta-analysis.• The summary statistic for each study is shown as a
square with a horizontal line indicating the confidence interval.
• At the bottom of the graphic the overall intervention effect estimate is represented by a diamond, with the center showing the point estimate and the horizontal tips illustrating the confidence interval.
• The significance of each study and the overall estimate are highlighted by whether they cross a vertical line of no effect.
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Example of a Forest Plot
*Originally published with the PRISMA Statement. (Liberati A, Altman DG, Tetzlaff J, et al. (2009) PLoS Medicine 6:e1000100)
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Limitations of Systematic Reviewsand Meta-analyses
• Limitations include the risk of misleading results if individual studies are biased or their reporting is not standardized.
• Although often useful for summarizing an intervention effect from randomized controlled trials, systematic reviews and meta-analyses are less effective for capturing adverse effects or summarizing observational studies.
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Rating the Strength of Recommendations
• GRADE– Used by the World Health Organization in its guideline
development process– Classifies strength of recommendations into strong or weak. A
strong recommendation means that based on the available evidence, clinicians are very certain that that benefits either do or do not outweigh the risks of an intervention.
– Website: http://www.gradeworkinggroup.org/intro.htm• SORT
– Used by the American Academy of Dermatology– Grades strength of recommendation into A, B, and C, with A-
level evidence based on consistent, good-quality, patient-oriented evidence and C based on consensus, usual practice, or opinion.
– Website: http://www.aad.org/education-and-quality-care/clinical-guidelines/guideline-development-process