Systematic Versus Rapid Review: The Impact of Database Coverage and Single Studies Selection on the Review's Conclusions

OBJECTIVES: Rapid reviews (RRs) offer a less rigorous and methodical approach to the process of reviewing literature in comparison to systematic reviews (SRs), which are currently a gold standard. The objective of this study was to test one methodological approach to RR and compare the results with SR conducted by Cochrane for exactly the same scope.

METHODS: The objective was to evaluate the effects of immunonutrition compared to standard formula feeding on mechanically ventilated adults with acute respiratory distress syndrome. The search strategy for RR was devised, and run in the Medline database. Single screening was conducted, while uncertainties were arbitrated by a senior reviewer. Once the screening was concluded, the list of included references was compared against the ones included by Cochrane. In contrast to RR, SR’s authors included multiple additional data sources, and adapted double studies selection. The analysts did not have prior access to Cochrane’s SR in order to minimize selection bias.

RESULTS: The search strategy generated 409 references, in contrast to 3,367 records retrieved in Cochrane’s SR. After screening titles and abstracts, 55 papers were reviewed in full, and 10 were ultimately included for further analyses. Using a simplified RR approach, the inclusion list was recreated with 100% efficiency. The cutdown of time and workload needed to complete the review were significant – RR was 16x quicker for titles and abstracts screening, and almost 5x faster in the full-text review phase. Using the dedicated software further optimized the screening process, which also accounted for time savings.

CONCLUSIONS: While in this case, the simplified approach allowed for obtaining identical results as extensive and thorough one, it is important to note that it carries some risks. The adaptation of RRs to the various decision-makers' needs is essential and depends on the requirements of the specific project.