How Do You Write a Literature Review for Clinical Research?
Conducting literature reviews is a crucial aspect of the medical device regulatory process. If you’re writing a clinical evaluation report (CER), you’ll need to collate and critically appraise the available evidence through a literature review.
In this article, we’ll outline the basic steps involved in writing a CER literature review and discuss a few tips that will help make the process easier for you. Ultimately, MEDDEV 2.7/1 revision 4 remains the premier guideline on best practices for writing clinical evaluation reports.
How To Write a Literature Review for Clinical Research
Step 1: Craft a Good Research Question
The first step in writing a literature review is to formulate an appropriate research question. This will guide your search for relevant literature by helping you narrow down your focus to exactly what you need. Research questions should be focused and not too broad, to ensure availability of a concentrated number of supporting research studies.
To write a good research question, you need to consider the following elements:
- What is the problem or issue that you’re trying to address?
- What are the key concepts or terms that you need to define?
- Who are the key stakeholders involved?
- What is the time frame for your review?
Upon careful consideration of these elements, you can start to develop your research question. For example, let’s say your medical device is a new type of pacemaker. Your research question might be, “What is the clinical effectiveness of this new pacemaker compared to existing pacemakers?”
To create a more precise research question, it’s best to follow the PICO framework. According to the PICO framework, your research question should contain:
- P: Patient population or problem
- I: Intervention
- C: Comparison
- O: Outcome
Using the PICO framework, your research question might be worded as, “In patients over fifty with heart failure, what is the clinical effectiveness of this new pacemaker compared to existing pacemakers?”
Now that you have a substantial and focused research question, you can move on to the next step.
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Step 2: Search for Relevant Literature
The next step is to search for relevant literature for your review. There are a number of ways to do this, but the most effective approach is to start with a systematic literature search. This involves using online databases to find all of the studies that meet your predefined inclusion and exclusion criteria.
Some of the most popular databases for medical device literature searches are PubMed and Embase. To conduct a search, you’ll need to use keywords and Boolean operators. Keywords are the words or phrases that describe your topic. Boolean operators are the words like “and,” “or,” and “not” that you can use to combine or exclude keywords in your search.
For example, let’s say you’re looking for studies on the clinical effectiveness of a pacemaker. Your keywords might be: “clinical effectiveness,” “pacemaker,” and “heart failure.” Your Boolean operators might be: “and,” “or,” and “not.”
To find studies that are specifically about the clinical effectiveness of a particular pacemaker, you could use the following search string in PubMed:
((clinical effectiveness) AND (pacemaker) AND (heart failure)) NOT ((animal study) OR (in vitro))
This search string would find all of the studies conducted on the clinical effectiveness of pacemakers in heart failure patients, and it would exclude any studies carried out on animal models or in vitro experiments.
Another important aspect is the exclusion criteria. Exclusion criteria are the characteristics of a study that would make it ineligible for inclusion in your literature review. For example, you might want to exclude studies that are not about human subjects, or you might want to exclude studies that are not published in peer-reviewed journals.
However, you must keep a record of all the excluded articles to comply with regulations. As a result, making sure exclusions are recorded systemically is critical, yet challenging. One method to do so is to create a separate “Excluded Studies” spreadsheet where you list all of the studies that you’ve excluded and why they were excluded. This will not only make it easier to keep track of your excluded studies, but it will also help you write the results later on.
Step 3: Appraise the Data
Once you’ve found all of the relevant studies, it’s time to appraise them. This means critically assessing each study to determine its usefulness, applicability, positive and negative points, and credibility. There are a number of ways to appraise studies, but one of the most popular methods is the GRADE approach.
To appraise a study using the GRADE approach, you’ll need to look at the study’s design, data, and results. You’ll also need to assess the quality of the evidence and make a judgment about the overall strength of the evidence.
The GRADE approach is a comprehensive and systematic technique to appraise studies, but it can be time-consuming. So, if you’re short on time, you should consider using our literature review tool, which reduces review times by 35% to 50% by automating every step of the process so you can enter the clinical investigation phase sooner.