Systematic literature reviews (SLRs) have always been amongst preferred tools for policy and decision makers owing to their quality of evidence as well as the ability to provide knowledge-base in terms of clinical practice guidelines as well as policy briefs. However, strict methodology followed during the conduct of an SLR can impact its duration, which may range anywhere from 0.5 to 2 years. (1) Along with the stringent guidelines, SLRs not only require two independent reviewers to execute all the necessary procedures of literature review, screening, data extraction and risk of bias appraisal; but also several technical experts, such as librarians, statisticians, subject matter experts, research coordinators and so on. (2)
Healthcare decision makers frequently require well-timed access to information in order to make informed decision regarding treatment and care. Even though SLRs are a preferred choice, they require a great deal of resources. In addition, the longer duration as required by SLRs may not harmonize with the needs of the researchers requiring a quicker review. For instance, the mean number of hours to conduct SLRs have been estimated to be 1,139 hours (range 216–2,518 hours) with a budget of about $100,000. (3)
‘Rapid reviews’ then come into the picture, which simplify or omit the stages involved in conducting SLRs to give quick information. Agency for Healthcare Research and Quality (AHRQ, US) defines a rapid review as “a form of evidence synthesis that may provide more timely information for decision making compared with standard systematic reviews”. (4,5) Today, rapid reviews are increasingly being used to synthesize evidence, particularly for making informed yet promising decisions in healthcare.(1)
Even though rapid reviews are emerging as a preferred tool for making urgent decisions, there is a dearth of evidence surrounding their methodology.(1,2) A recent scoping review of rapid review methods has reported their conduct to be complicated. Findings of this review show that many important steps in an SLR are often omitted during rapid reviews, such as protocol application, limited literature search, limited inclusion criteria, and lack of quality appraisal among others. Rapid reviews also involve limited interpretation of findings and may cause bias. Many articles in the literature poorly report the methodologies of rapid review, thus warranting further improvement.(2) Therefore, clear gaps exist in transparency in and knowledge about the reliability of rapid reviews.(1) However, there are some areas where rapid reviews can be helpful, such as broader PICO questions, novel or emerging research topics, updates on previous reviews, critical topics, further exploration of a policy or practice using some systematic review methods, and so on.(5)
The increasing preference for rapid reviews and their application into urgent decision-making emphasizes the need to further explore their characteristics and uses. While researcher opting for rapid reviews are answerable about the time-sensitive needs of the health decision makers they work for, they must do it in line with the expected methodological rigor. For this purpose, methodological research and standard development is crucial. (6)
In conclusion, not only the methodologies, but also their consequences should be further investigated in order to better implement rapid review methods for making timely decisions. A prospective study, which can compare the results of rapid reviews to those achieved from an SLR around the same topic, can be conducted (1) and will be interesting to look at.
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- Khangura S, Konnyu K, Cushman R, et al. Evidence summaries: the evolution of a rapid review approach. Syst Rev 2012; 1:10.
- Tricco A, Antony J, Zarin W, et al. A scoping review of rapid review methods. BMC Medicine 2015; 13:224.
- Petticrew M, Roberts H. Systematic reviews in the social sciences: a practical guide. Malden, MA: Blackwell Publishing Co.; 2006.
- Agency for Healthcare Research and Quality (AHRQ).
- Systematic Reviews & Other Review Types. Temple University.
- Cochrane Rapid Reviews Methods Group (RRMG).
Written By: Ms. Tanvi Laghate