Date	Event	Description
9 April 2013	New citation required but conclusions have not changed	Searches of CENTRAL and Specialised Register were rerun. No new studies were found. Minor edits made. Conclusions not changed.
9 April 2013	New search has been performed	Searches of CENTRAL and Specialised Register were rerun. No new studies were found.
28 October 2008	New search has been performed	Searches re‐run and no new trials found. Updated search strategy.
19 September 2008	Amended	Converted to new review format.
11 November 2007	New search has been performed	Re‐ran searches; no new trials found. Updated search dates. Conclusions remain unchanged.
8 November 2006	New search has been performed	Made minor copy edits to table of Characteristics of Included Studies, table of Excluded Studies, reference list, and text. Added Plain Language Summary and acknowledgements. Updated search strategy. Added link to results table and linked an in‐text citation. Changed dates of last search and most recent update. No new trials found; conclusions remain unchanged.
5 August 2004	New search has been performed	No new trials found. Updated with minor formatting changes.
4 November 2002	Amended	Synopsis incorporated into text.