Optimising process and methods for a living systematic review - 30 search updates and three review updates later.

Living systematic reviews (LSR) are systematic reviews that are regularly updated, allowing new evidence to be incorporated as it becomes available. LSR are ideally suited to policy-relevant topics where there is uncertainty and new evidence will likely impact the interpretation and/or certainty of outcomes. To be of benefit, updates must be published in a timely manner. Many LSR do not publish more than one update. As authors of a systematic review that has been 'living' for two years, with monthly search updates and three full updates published in this time, we describe the steps in our LSR process with the aim of informing and assisting authors carrying out their own regularly updated LSR. Key features of the process that require consideration are as follows: specifying the frequency of searches and triggers for full updates in the protocol; stakeholder input; publishing and disseminating monthly search findings. A strong team, incorporating methodological and topic expertise, with core members that meet regularly is essential. Regular search updates make it important to have a clear cyclical schedule of activity. To achieve timely updates this process should be streamlined, for example, using automated monthly searches, and systematic reviewing software for screening. LSR provide a unique opportunity to incorporate stakeholder feedback; as soon as a review update is complete you may be planning your next, and can incorporate useful feedback. We suggest seeking feedback on your findings and methods and, where appropriate, incorporating them with transparency.