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What is a living systematic review? James Barker, Senior Assistant Editor at F1000, introduces us to this novel article type explaining how it can help us keep up to date with the latest evidence.  

What are they and why do we need them?

The easiest way to describe Living Systematic Reviews (LSR) is to simply define them. Cochrane, the group that first proposed LSRs, have come up with the following:

“a systematic review that is continually updated, incorporating relevant new evidence as it becomes available”

Currently, the majority of systematic reviews are static, standalone snapshots of the evidence in a given field at the time the study was conducted. They are a powerful tool to summarise and analyse all available evidence in a given field or related to a particular question. This high-quality evidence, however, comes with a cost… time.

Conducting systematic reviews is a lengthy process, taking on average 67.3 weeks to be published. This obviously leaves a significant amount of time where new evidence could become available but is not captured. This problem is made worse by the fact that the rate of publication for clinical trials, the articles that form the majority of evidence systematic reviews  draw from, is around 75 per day.

We therefore have a problem where we have a huge wealth of evidence to draw on, some of which will inevitably be overlooked by a systematic review. This webinar from Cochrane provides a more detailed overview of the current problems.

So how do we solve this problem? A group from Cochrane proposed a new concept in 2014 in a paper published in Plos Medicine to address this issue… Living Systematic Reviews.

This new article type would work the same as a standard SR, providing the same benefits; however, following initial publication the literature would continue to be monitored, with new findings being added as and when they become available. This constant surveillance allows the latest evidence to be presented at all times, and allows further validation of previous conclusions based on the most recent findings in a given field. This not only benefits the literature, ensuring it is as up-to-date as possible, but also ensures that clinical guidelines, which are heavily influenced by SRs, are drawing on the most recent clinical evidence.  

With patients in mind

An analogy for the current situation is a scenario of a patient attending a clinic. When a patient presents to their doctor, the doctor will have access to their medical history and then will gather new evidence, from what the patient describes, clinical test, observations etc. In some cases, the doctor could make a correct diagnosis purely from the medical history of the patient, however, without collecting new data the doctor may miss key information leading to a misdiagnosis.

This is similar to the current situation with traditional SR’s, while a stand-alone SR may capture all the relevant information and lead to a correct conclusion; there is, however, the possibility that in the time between screening being finished and the article being published, new evidence becomes available. This evidence may have no effect on the previous conclusion or could bring the previous conclusion into question.

We are unlikely to have a situation in the clinic where clinicians won’t collect new data to confirm or identify a novel diagnosis, and yet we have a situation where articles that directly influence clinical practice do not draw from the most up-to-date evidence.

The literature, much like patients, is a living entity that is constantly changing and evolving. It is time we start treating it as such and monitor the literature in real time as we would the patients we are ultimately trying to help.

Making LSRs a reality

LSRs come with challenges, both in terms of performing them and in their publication. Continual surveillance and the need for subsequent updates to the article obviously increases the workload, both for the authors and publishers. This is likely to improve as both parties gain more experience with this new article type, as new workflows and tools are developed to facilitate their publication.

Other potential challenges include changes to the author list through the life course of the LSR, and when an LSR should cease to be ‘living’. Given the novelty of LSRs, a certain level of watchful waiting will be required, while we can try to foresee as many potential issues as possible it is likely that some simply won’t come to light until we start publishing and updating these articles.

Recently, I presented our plans to implement LSRs on F1000Research to Cochrane’s Living Evidence Network in a webinar, outlining the challenges we have identified and how we aim to address them.

So where are we now?

Throughout the year we have been working on building our capabilities to publish LSRs through developing workflows and making adjustments to our guidelines. In June, we launched our Living Evidence collection. This will be the home for all our LSRs and will also provide a space for other articles related to Living Evidence in general.

In August, we published our first LSR update from Counette et al., which comes with a rather special addition in the form of a living figure. This presents live updates of the literature search via an interactive map, while the article itself is updated every 6 months.

Moving forward from here, we are currently working on finalising our guidelines for LSRs before adding them to our website. In addition, over the coming months we will be publishing a series of blogs on how to publish LSRs on F1000research addressing everything from what to include on your submission to peer review.

LSRs have significant potential to benefit both scientific literature and clinical practice, and it is our aim to work to build our capabilities to facilitate these article types. It is our hope that our work will allow F1000Research to become the home for LSRs.

Make sure you read the living systematic review and take a look at its special interactive figure, clearly mapping out the epidemiological studies that report on adverse congenital outcomes (blue) or Guillain-Barré syndrome (red) associated with Zika virus exposure.