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RSV has outcomes similar to influenza in older adults.

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To know whether you can trust a systematic review, look for acronyms like PRISMA and NOS (even if you don’t know what they stand for) that suggest systematic methods and outcomes you can probably trust.

You may not think much about the riveting tool used to put together the next airplane you step onto, but we can all agree that it’s important for that tool to do its job correctly. Similarly, unless you’ve written a systematic review, you’ve probably never considered how to appropriately select studies and integrate them to form conclusions. But just like building an airplane, much depends on using the right tool for the job.

Case in point: in December, the journal Vaccines published a systematic review (SR) of 16 observational studies on the relative risks of hospitalization and/or death from respiratory syncytial virus (RSV) versus influenza in adults over the age of 60. Sometimes, those of us in the EBM-world look down on observational studies as giving less certainty than randomized controlled trials, but the inclusion of over 750,000 patients makes this an impactful observation indeed. The results are pretty straightforward: it looks like RSV is statistically quite similar to influenza in terms of risks for older people. (In other words, RSV isn’t as deadly for older adults as the original COVID-19 strain.) This information may prove helpful if vaccines or effective treatments ever become available for RSV in adults.

But for now, what is interesting from an EBM point of view are the methods used to select and aggregate the studies included. When we evaluate the methods section of a randomized controlled trial, we often consider why researchers choose one technique over another. For systematic reviewers, culling the irrelevant trials and appropriately combining data are key parts of the methods section. Checklist tools became popular about 10 to 20 years ago as a way to standardize data reporting from disparate sources and answer bigger questions about diagnosis and management. These authors used one such tool for conducting systematic reviews, PRISMA (Preferred Reporting Items for Systematic Reviews and Meta Analysis), to describe both how they searched for articles and winnowed them down from an initial 2,295 articles to the final 16 reviewed. Articles that did not meet the SR criteria because the subjects were too young, had inadequate proof of RSV infection, or other predefined criteria, were excluded. After selection, another checklist (the NOS scale, Newcastle-Ottawa Scale which looks at bias in observational studies) was used to evaluate for bias in the articles selected. This tool quantifies factors that might affect publication and other biases in the articles. The authors report that all articles they include scored an 8 or 9 on the scale, giving them a low risk of bias. In the grand scheme of things, if this SR is deemed high quality research, it might be included when someone looks at all the evidence about RSV in older adults as part of a GRADE (Grading of Recommendations, Assessment, Development and Evaluation) analysis — another type of checklist — to decide if it can inform an expert recommendation, presumably from a society of infectious disease or geriatric experts, as to whether we should evaluate-for or treat RSV.

You don’t need to memorize these acronyms or their checklists any more than you need to know how rivets support an airplane fuselage. You just need to be able to know if you can trust that the authors designed a good rivet, so to speak. The bottom line here is that this systematic review was done using trusted methods and confidently suggests RSV is about as dangerous as influenza for older adults.

For more information, see the topic Respiratory Syncytial Virus (RSV) Infection in Adults in DynaMed.
CMA members have access to DynaMed, a point-of-care reference tool valued at US$399 per year, as part of their membership.

Do you have a question on these or other clinical topics? Contact the Ask a Librarian team to request a literature search.

About the author(s)

Written by written by Dan Randall, MD, Deputy Editor at DynaMed

Edited by Alan Ehrlich, MD, Executive Editor at DynaMed and Associate Professor in Family Medicine at the University of Massachusetts Medical School; Katharine DeGeorge, MD, MS, Deputy Editor at DynaMed and Associate Professor of Family Medicine at the University of Virginia; Nicole Jensen, MD, Family Physician at WholeHealth Medical; Vincent Lemaitre, PhD, Senior Medical Writer at DynaMed; and Sarah Hill, MSc, Associate Editor at DynaMed.

DynaMed is a clinician-focused tool designed to facilitate efficient and evidence-based patient care. Rigorous, daily review of medical literature by physician and specialist staff ensures timely and objective analysis, synthesis and guidance. DynaMed includes drug content from Micromedex, Canadian and international guidelines, and clinical images. CMA members have access to DynaMed, a point-of-care tool, included with their membership ― a tool valued at US$399 a year.

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