|RESEARCH SERIES ARTICLE
|Year : 2022 | Volume
| Issue : 2 | Page : 124-126
The art and science of writing narrative reviews
Department of General Medicine, Dr. Moopen's Medical College, Wayanad, Kerala, India
|Date of Submission||10-Oct-2022|
|Date of Decision||25-Oct-2022|
|Date of Acceptance||30-Oct-2022|
|Date of Web Publication||06-Dec-2022|
Dr. Aneesh Basheer
Department of General Medicine, Dr. Moopen's Medical College, Wayanad - 673 577, Kerala
Source of Support: None, Conflict of Interest: None
In this age of evidence-based medicine, systematic reviews are considered the highest level of evidence. However, traditional narrative reviews continue to have an important role in medicine. While narrative reviews have inherent shortcomings in terms of nonstandardized literature search, potential bias in the appraisal of retrieved articles, and interpretation of findings, they serve as sources of quick up-to-date reference for specific areas of interest of readers. Well-conducted reviews could inform readers about gaps in existing literature and areas that need new primary research. Crafting a narrative review requires a blend of good scientific approach and the skillful art of presentation. This article aims to provide an overview of the need for narrative reviews and strategies to equip potential review authors complete an effective narrative review.
Keywords: Critical appraisal, evidence-based medicine, meta-analysis, systematic reviews
|How to cite this article:|
Basheer A. The art and science of writing narrative reviews. Int J Adv Med Health Res 2022;9:124-6
| Why do we Need Reviews?|| |
Reviews summarize up-to-date information about a topic or question of interest. This definition is simplistic but not representative. Unlike several decades ago, the present age is characterized by information overload. In just 17 years, there was an eight-fold increase in the number of articles on obesity indexed in the Web of Science. The implications of this information overload are diverse, including the helplessness of busy readers to be abreast of the latest developments and perform detailed evaluations of all papers in a given area of interest. This problem may be addressed to a large extent by the availability of good quality and timely reviews. Besides, reviews attract more readership and citations, adding to the metrics of individual authors and journals that publish them. Good reviews can be the source of new research questions since they identify research gaps and limitations in the existing literature.
| Are All Reviews the Same?|| |
Traditional reviews are narrative in nature. They are considered nonsystematic because they do not have a prespecified methodology and systematic approach to the types of data that will be reviewed. The review authors often describe the topic of interest under traditional headings of global and/or local relevance, epidemiology, etiology, approach to diagnosis and/or management, and future implications. There may be deviations from this typical hierarchical approach based on individual writing and presentation skills. Topics on which nonexperimental and basic science research rather than interventional or controlled trials are available seem best suited for narrative reviews. In simple terms, narrative reviews are predominantly qualitative in their approach.
Systematic reviews, in contrast, have standard guidelines for planning and reporting. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) is the most widely followed guideline by authors performing systematic reviews. The hallmarks of systematic reviews are a prespecified and often publicly available protocol detailing the methodology adopted for the review with the following information: search terminology, databases that will be searched, focused and usually single research question, systematic and objective evaluation of bias in the literature reviewed, and critical appraisal of the collated literature. In some cases, the available data from several studies included in such reviews permit pooled statistical analysis, providing a single meaningful estimate of outcomes that is more precise than outcomes reported by the included individual studies. The latter technique is referred to as a meta-analysis. These characteristics make a systematic review predominantly quantitative, although qualitative assessments of included studies, albeit in a more organized and objective manner, are an integral part of these reviews.
| Should i Write a Review?|| |
Identifying an area of interest is central to writing a review. The topic must be interesting, and on an area, the author is passionate about. It must also be important to the target audience. Once a topic is identified, it is good to contemplate whether a review of it is indeed necessary.
Pautasso et al. described an interesting matrix with the amount of published research on a topic on the Y-axis and the amount of reviews on the topic on the X-axis. This matrix leads to the following possibilities.
Scanty amount of published research + very few reviews on the topic
This means new research questions need to be identified in this area, and good research needs to be done. This is, therefore, not a topic suited for review. An exception is rare disorders where further large-scale primary research may not be feasible.
Scanty amount of published research + plenty of reviews
This indicates the need for a review stressing the requirement for more primary research.
Plenty of published research + very few reviews on the topic
This situation is ideal for a comprehensive review.
Plenty of published research + plenty of reviews
This situation calls for a review of reviews (scoping reviews).
| Some Key Points to Get the Review Right|| |
Now that the decision to write a review has been made, many skills come into play to define the art of writing it. The following steps are crucial to completing a good review.
Search the literature
The heart of a review is the thoroughness of its search. Use appropriate keywords and include multiple databases such as MEDLINE, EMBASE, Scopus, Cochrane library, and any others relevant to the review. Using the Medical Subject Headings (MeSH) terms and different search strategies may help retrieve all relevant articles on a particular area. However, the broader the topic, search becomes exhaustive and difficult to limit. Hence, choosing a focused area is paramount to bringing out a good review. At this stage, it is also important to use referencing software such as Zotero or Mendeley to ensure that search results are saved for easy retrieval and citing in the review later. It is also a good practice to make a list of articles that are not accessible as full texts but should definitely be included in the review so that the author can find ways to get full texts later on. During the search, it is likely that other reviews on the same topic might be encountered. These are invaluable as they help identify primary papers that might have been missed during your search. Such reviews also help authors approach their own reviews with a different perspective.
Create a skeleton
The basis of your review is what you infer from different articles identified during the search. A table or chart with provisions for documenting the article title, first author, year of publication, journal, primary research question, pertinent methodology, and major results helps to structure the review later [Figure 1].
This skeleton will provide most of the information needed for completing the first draft of the review. Although not a part of the final review article, it allows quick comparisons between studies and compiling studies with similar results.
| Decide Your Style|| |
A narrative review has no specific reporting format, unlike systematic reviews. It is, therefore, important to decide how you wish to present your review. If the topic is very broad, one useful and time-tested approach is to divide the review into headings such as introduction, epidemiology, etiopathogenesis, clinical and laboratory features, management, and complications. This works well for individual diseases or broad topics. However, a different approach may be needed for more focused topics such as the diagnostic approach to disease. Outlining the relevance of the disease, followed by sections on existing diagnostic methods, gaps in the available methods, and then a review of the advantages and limitations of recent methods would be a reasonable format. A review addressing the long-term complications of COVID-19 would probably need a background outlining the burden of long COVID, gaps in current understanding, including controversies around definitions and diagnostic criteria, a summary of existing data on the different manifestations of long COVID, and challenges related to diagnosis and management. In short, unlike a systematic review, narrative review authors enjoy greater writing flexibility; however, the lack of standardized reporting guidelines confers an increased likelihood of bias in the review.
Critically evaluate the literature
Listing out all the relevant papers makes a review monotonous and ineffective. A critical appraisal of important articles with respect to the methodology is crucial since this makes the results of a review useful to readers. While the process of critical appraisal is streamlined and prespecified in systematic reviews, such robustness is unusual in narrative reviews. The authors must ensure an unbiased, objective analysis of all the literature they have decided to include in the review. For example, the Cochrane risk-of-bias (ROB) tool is widely used by systematic review (specifically of randomized controlled trials) authors to evaluate individual studies included in their reviews. This incorporates several crucial elements such as randomization, concealment of allocation, blinding issues, follow-up, and attrition leading to a judgment about the degree of ROB in the paper. Narrative review authors could use similar principles while critically appraising the articles they have included in their review. Further, a synthesis of the included studies is useful to convey relevant information to readers. Synthesis involves analysis of methodological aspects and results of studies followed by summarizing common themes and outcomes. It is also important to include papers that have contrasting views or results; not only does this make the review more objective but it also helps identify controversial areas and develop new research questions in the field. These could be potential outcomes of the review.
Use a framework to ensure good validity of your review
Although authors of narrative reviews are not bound to follow PRISMA or similar checklists, it would be a good exercise to use these while preparing the review. The scale for the Assessment of Narrative Review Articles has been developed by Baethge et al. to aid in the quality assessment of narrative reviews; however, it warrants field testing for validity before recommending widespread use.
Use simple math to convey messages
Despite being predominantly qualitative, narrative reviews need not be devoid of numbers. Presenting important outcomes or results as easily understandable effect estimates such as odds ratios, relative risks, and number needed to treat will not only enhance the credibility of the review but also provide data that could be of immediate use to readers in decision-making and patient care.
Narrative reviews have inherent limitations in terms of objectivity, completeness of literature search, and interpretation of findings. Besides these, any specific limitations must be disclosed and discussed in terms of why it happened and what was done to address it. This increases the genuineness of the review process and enables authors of future reviews to improve their methods.
Get the review reviewed
Although most articles submitted to journals undergo peer review, it is good to get your draft informally reviewed by colleagues and other experts in the field. This helps authors get different perspectives, and new styles of presenting the review, and sometimes, even discover important papers that were missed during the search.
Review authors must be careful not to make conclusions that are prejudiced and not based on the literature they have reviewed and presented in the paper. At the same time, readers must be left with key messages derived from a critical appraisal of the literature and unanswered questions. A useful and interesting way to end the review is by listing down specifically what future reviews on the topic should focus on; these could be related to different types of studies, study participants, disease spectrum, or outcomes.
To conclude, despite its limitations and lower validity in terms of evidence, narrative reviews have an important place in modern scientific approach. Good reviews provide a quick reference for up-to-date and comprehensive information on an area of interest. When written objectively, they make useful tools to guide decision-making. Importantly, narrative reviews discussing evidence gaps and limitations are often starting points for new, unanswered questions that could potentially lead to pathbreaking primary research.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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