Explanatory note 1
The practice of arbitrarily updating all reviews is now replaced by a review-by-review appraisal that assesses whether the review will include new data, new methods, new analyses or corrections to the previous review (Garner 2016). The update will address a similar PICO, however, it may necessitate modifications to accommodate developments in the topic area (Garner 2016).
Garner P, Hopewell S, Chandler J, MacLehose H, Akl E, Beyene J, et al. When to update systematic reviews and how to do it: consensus and checklist. BMJ 2016;354:i3507.