In PLoS Clinical Trials, vol 1, issue 7: doi:10.1371/journal.pctr.0010036
In Box 2, Reference [52] should be corrected to [22]. References [18-21] in the text should be corrected to [18-22]. The six successive references from [22] to [27] in the text should be corrected to [23] to [28]. Finally, the current reference [28] in the text should be corrected to [14].