Date	Event	Description
15 May 2008	New citation required but conclusions have not changed	The list of authors has changed.
15 May 2008	New search has been performed	This review has been updated (new search in March 2007) from a previously published review (Vist 2005). Thirty new studies with 45 comparisons have been included in this update. A total of 85 studies with 136 comparisons are included. These studies report on 86,640 patients who have been randomised to treatment within RCTs compared with 57,205 similar patients who received similar treatment outside of the trial.
22 February 2007	Amended	Converted to new review format