CA - SR - Results

Critical Appraisal of a Systematic Reviews - Results

RESULTS OF A SYSTEMATIC REVIEW

• Qualitative Summaries

  • the first use of a systematic review is to look at all the literature on a topic side by side to compare the study designs, populations and ultimately the results. If the results of a group of studies cannot be combined into a pooled estimate, then this will be the only result of the review - a listing of the individual results. It is possible to do a "vote count" of trials which show a benefit vs. those that don't, but factors such as sample size and study validity need to be taken into account so that small or invalid trials do not "count more" than larger and invalid ones.

  • it's important to review this information to get an understanding of what studies were included in the review. you will also want to review a list or table of EXcluded studies so that you know which evidence the authors did not use in their review.

• Quantitative Summaries

  • the most sought-after result of a systematic review is a pooled analysis of the data from the included studies. This is done through the statistical technique of meta-analysis.

  • meta-analysis can be performed on both continuous and dichotomous data, so make sure you know what you're looking at.

  • the review will frequently contain a Forest Plot (try these pages: here or here) for showing these results. Make sure you understand the orientation of this plot - which side means benefit, and what type of statistic is it showing (a weighted mean difference for continuous data or a relative risk for dichotomous data, e.g.)

CHECK YOURSELF

Meta-analysis should be reported with every systematic review, because it can fix the problem of too much heterogeneity between studies.

True False

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