Date	Event	Description
3 July 2017	New search has been performed	A search of the Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Trials Register and the WHO ICTRP did not identify any potentially eligible trials.
3 July 2017	New citation required but conclusions have not changed	Minor changes have been made throughout the review, including the re‐formatting of the plain language summary in line with more recent guidelines.
4 March 2015	New search has been performed	A search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's haemoglobinopathies Trials Register did not identify any potentially relevant trials for inclusion in the review.
4 March 2015	New citation required but conclusions have not changed	The study by de Araujo has been moved to excluded studies following unsuccessful attempts to contact the authors for further clarification (de Araujo 1994).
27 April 2012	New citation required but conclusions have not changed	Minor changes to the text have been made throughout the review.
9 February 2012	New search has been performed	A search of the Group's Haemoglobinopathies Trials Register did not identify any trials eligible for inclusion in this review.
5 January 2010	New search has been performed	A search of the Group's Haemoglobinopathies Trials Register did not identify any trials eligible for inclusion in this review. Searches of LILACs and www.ClinicalTrials.gov did not identify any trials eligible for inclusion in the review. The Background section has been updated.
18 April 2008	New search has been performed	A search of the Group's Haemoglobinopathies Trials Register did not identify any trials eligible for inclusion in this review. Comments by the CFGD Group's Medical Statistician have been addressed.
18 April 2008	Amended	Converted to new review format. The original 'Synopsis' has been replaced with a new 'Plain language summary' in line with guidance from The Cochrane Collaboration.
21 February 2007	New citation required and conclusions have changed	Review first published