What is a systematic review?
It’s widely acknowledged that health care decisions should be made on the basis of the best available evidence. However, with a large and growing body of research information out there of variable quality, it can be time-consuming and overwhelming for healthcare staff and researchers to find that best available evidence. Systematic reviews help overcome this problem, and are important tools in providing evidence-based healthcare.
Systematic reviews aim to identify, evaluate and summarize the findings of individual studies, in a systematic and unbiased manner, thereby making reliable evidence more accessible to decision makers.
How do I go about starting a systematic review project?
In order to create a true systematic review you need to first identify your research question and gather a team of people to fulfill the different roles. Having a team of people helps with covering the different skills required for the different elements of the review and minimizes the risk of bias being introduced. Team members could optimally include:
What is a systematic review protocol?
All good systematic reviews will start with a protocol. A protocol is a plan that sets out in advance the rationale for a review, its objectives and the methodology to be used with the aim of minimizing bias. The Cochrane Collaboration define bias as 'a systematic error, a deviation from the truth, in results or inferences'. Creating a solid protocol and adhering to it, can help minimize the risk of any bias being introduced into the systematic review process.
The protocol will outline the steps to be taken to locate, select and critically appraise studies and how study data will be collated and analyzed and reported, making the review transparent and therefore reproducible by other researchers.
The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Statement has been developed to make sure that all relevant methodological information is included in published reviews and, as a result, can also help guide reviewers’ understanding of the systematic review process and its main features. A by-product of this statement is the PRISMA-P checklist, a useful guide to follow when writing a protocol.
In 2021, PRISMA also published its guidance for literature search reporting.
Registering your review will hopefully avoid others carrying out similar reviews on the same topic, and likewise you can use publicly available review registers to check that you are not planning to duplicate work already being carried out by other researchers.
The two best sources of registered reviews are:
2. Joanna Briggs Institute - JBI 's Systematic Review Register
What are the stages of a systematic review?
High quality systematic reviews are defined in advanced by a protocol (see above) that maps out how the reviewers will:
Hemingway, P. (2009) What is a systematic review? http://bit.ly/2udFvYb
Framework for systematic reviews
Another useful framework is the SALSA framework developed by Grant and Booth (2009). It gives an overview of the main components of the evidence synthesis process:
Grant, M.J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91-108. https://doi.org/10.1111/j.1471-1842.2009.00848.x
What is evidence-based healthcare?
The most common definition of Evidence-Based Healthcare (EBH) is from Dr. David Sackett. EBH is “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient" ( BMJ 1996;312:71)
Why is it important?
Population-based outcome studies have found that therapies that are evidence-based have more positive effects on patient care than opinion-based healthcare. For example, heart attack survivors prescribed aspirin or beta-blockers have lower mortality rates than those who aren’t prescribed these drugs.
How do we go about it?
EBH comprises of 5 steps:
Step 1. A decision needs to be made arising from a patient’s care or service development.
Step 2. You formulate a focused question, accounting for your population group, problem, intervention and any comparisons or outcomes.
Step 3. You identify the appropriate resources to search for the best evidence — here’s where the library can help the most.
Step 4. Critically appraise the evidence- the library can help you here too!
Step 5. Implement in practice, if applicable.