Module Components

• Learning Activities

Topics

• Critical Appraisal Principles
• Systematic Review Appraisal
• Randomized Control Trial Appraisal
• Cohort Study Appraisal
• Case Control Study Appraisal
• Module 8 Self-Review

NRSG 790-Methods for Research and Evidence-Based Practice

Module 8: Critically Appraising Quantitative Evidence

Systematic Review Appraisal

Frequently there will have been more than one study addressing a particular health question. In such circumstances it is logical to collect all these studies together and base conclusions on the cumulated results. However the same scientific principles as would be expected in the original studies need to be applied to the identification, sorting and analysis of potentially relevant studies. This is what is meant by a systematic review. The most obvious sign that a review is systematic will be the presence of a methods section. Meta-analysis is the statistical process of combining the results from several studies that is often part of a systematic review.

Advantages

• Exhaustive review of the current literature and other sources (unpublished studies, ongoing research)
• Less costly to review prior studies than to create a new study
• Less time required than conducting a new study
• Results can be generalized and extrapolated into the general population more broadly than individual studies
• More reliable and accurate than individual studies
• Considered an evidence-based resource

Disadvantages

• Very time-consuming
• May not be easy to combine studies

Example

• Pittler MH, Guo R, Ernst E. Hawthorn extract for treating chronic heart failure. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD005312.

This systematic review analyzed fourteen studies (randomized, double-blinded, and placebo controlled) that used hawthorn leaf and flower extract monopreparations to determine whether there is any benefit or harm in using hawthorn extract to treat chronic heart failure when compared to placebo. The authors determined that hawthorn extract provides “significant benefit in symptom control and physiologic outcomes” when used as an adjuvant treatment for chronic heart failure.

 Systematic Review Critical Appraisal Tool - See "Tool" in Lesson Plan under "Recommended Reading"