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“Living” systematic reviews: are they the future?

Posted on 13th March 2014 by

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A couple of weeks ago, this paper was published in PLOS medicine, which laid out a framework for a new kind of systematic review, which rather than remaining stagnant for 2 years or more then being updated, was constantly changing as new evidence came to light. Given that one of the biggest criticisms of the current way of conducting systematic reviews is the time they take and how they are out-of-date before they are even published, this could help adapt the current systematic review format in light of the exponential increase in the number of papers published per day.

In Elliot et al.‘s paper, they lay out the delay from publication of a new trial to inclusion in a systematic review in their Figure 1, which shows a median of 2.5-6.5 years. Evidently, this could leave clinical practice and recommendations several years behind the available evidence.  As they describe in their paper, the concept of living systematic reviews goes beyond keeping them updated. It involves changing the way they are published and the workflow of the teams involved. This includes semi-automation of screening,  They also suggest using different statistical methods to the ones currently used, to allow the review to be kept up to date.

They also have a fantastic diagram of the health knowledge ecosystem (Figure 2), which provides an insight into how knowledge moves around and influences clinical practice. The ‘knowledge cycle’ at the centre will be familiar to many of us, but it is the outer cycle that is emerging that is of more interest. This makes use of the capacity of the internet for big data and constant updates.

Presently, the time taken for primary research to influence clinical practice, at least as measured by time to be included in a systematic review, is several years. Living systematic reviews have the potential to get the latest research insights into clinical practice faster.


[1] Elliott JH, Turner T, Clavisi O, Thomas J, Higgins JPT, et al. (2014) Living Systematic Reviews: An Emerging Opportunity to Narrow the Evidence-Practice Gap. PLoS Med 11(2): e1001603. doi:10.1371/journal.pmed.1001603


Alice Buchan

I'm Alice, a fifth year medical student at the University of Oxford. I did my 'intercalated year' focusing on immunology. At the moment, my particular interests are in immunology, reproductive biology, and obstetrics. View more posts from Alice

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