| Date | Event | Description |
|---|---|---|
| 27 October 2009 | New citation required but conclusions have not changed | Substantive methodological amendment following updated literature search between 1998 and 2008. Conclusions not changed. |
| 25 June 2008 | New search has been performed | Searches updated to June 2008 and additional publications reporting longer follow‐up to original trials were identified and included. No new trials identified. |
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