LibGuides: NUTR 369: Systematic Reviews: Intro

What is a Systematic Review?

Systematic a: methodical in procedure or plan <a systematic approach>

<a systematic scholar>

b: marked by thoroughness and regularity <systematic efforts>

Review a: a retrospective view or survey (as of one's life) b: renewed study of material previously studied (2) : an exercise facilitating such study

"A systematic review attempts to collate all empirical evidence that fits pre-specified eligibility criteria to answer a specific research question. It uses explicit, systematic methods that are selected to minimize bias, thus providing reliable findings from which conclusions can be drawn and decisions made. Meta-analysis is the use of statistical methods to summarize and combine the results of independent studies." - Cochrane Collaboration

Guides For Writing Clinical Systematic Reviews

Cochrane Handbook for Systematic Reviews of Interventions
The official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.
PRISMA
PRISMA stands for Preferred Reporting Items for Systematic Reviews and Meta-Analyses. It is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram.
Finding What Works in Health Care
Institute of Medicine (IOM) recommends 21 standards for developing high-quality systematic reviews of comparative effectiveness research. The standards address the entire systematic review process from the initial steps of formulating the topic and building the review team to producing a detailed final report that synthesizes what the evidence shows and where knowledge gaps remain.

More Helpful Guides

Lecture Slides

Systematic Reviews: Theory & Practice
Introductory lecture slides

A Brief Introduction to Evidence-Based Medicine

The EBM Cycle

The following image represents the hierarchy and availability of the different types of research evidence and studies. As you can see, Systematic Reviews and Meta-Analysis are the highest level of evidence, but the least populous of all the study types.

View the following presentation for a brief introduction to the EBM Cycle

What's Required?

Guidelines for strict clinical systematic reviews do not always work well for the fields of nutrition, public health or mental health. It is worthwhile, however to be familar with those guidelines and then modify the searching and the types of studies included to fit these disciplines. See the Guides for Writing Systematic Reviews box to the left.

There are guides for systematic reviews in non-clinical topics such as nutrition and public health reviews. You can see these on one of our other systematic review guides, Systematic Reviews for Nutrition and Public Health.

But just as in clinical or bench research, a detailed methodology of your search strategy, results and inclusion/exclusion criteria must be included in your review so that it is reproducible. PRISMA standards require you to fill out a flow diagram and provides a helpful checklist to determine if your SR is complete.

How Long do They Take?

Remember the evidence pyramid and how few systematic reviews and meta-anaylses there are? This can be attributed to a few factors:

Many topics do not have enough lower-level research completed to create a thorough SR
Many topics do not lend themselves to "pure" SRs
Requirements for SRs are stringent, causing many attempts to fall short in methodology
High-quality SRs take a lot of TIME and effort.

The Cochrane Collaboration estimates about a year to complete the process, and this is often by teams of people working together on one review.