| Date | Event | Description |
|---|---|---|
| 27 March 2014 | Amended | Contact details updated. |
| 21 July 2009 | Amended | New search date added |
| 20 October 2008 | Amended | Converted to new review format. |
| 15 June 2006 | Amended | Minor update: 15/05/06 New studies found but not yet included or excluded: 28/02/06 Conclusions changed: 28/02/06 Searches have been updated and new trials identified, but they will only be included in the analysis when individual patient data has been obtained. |
| 25 November 2003 | New citation required and conclusions have changed | Substantive amendment |
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