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Research Methods & Reporting

CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials

BMJ 2010; 340 doi: https://doi.org/10.1136/bmj.c332 (Published 24 March 2010) Cite this as: BMJ 2010;340:c332

Inclusion of prospective trial registration in the new version of the CONSORT Statement.

We would like to congratulate you on the 2010 revised version of the
CONSORT Statement. It is indeed essential to regularly evaluate and update
such standards. The CONSORT 2010 Statement (1) included a new item (item
23) on trial registration in which the registration number and name of
trial registry should be reported. We applaud you for adding this very
important item. However, timing of registration is another important issue
to be analyzed. A prospectively registered trial is one where the trial
start date (actual or anticipated) is the same or after the date of trial
registration. Conversely a retrospectively registered trial is one where
the trial start date (actual or anticipated) is before the trial
registration date.

To achieve the principal goal of trial registration (ie preventing
the outcome bias), it is essential that trials are registered
prospectively. However, this is not currently always the case, as
illustrated by the experience of the Australian registry (2), which
reports that more than half (on average 59%) of 2618 trials registered
between 2006 and 2009 were registered with a median delay of 146 days.

Retrospective registration confuses the message about the importance
of prospective registration and may lead some within the research
community to think that retrospective registration is an acceptable long-
term solution. Journal accepting retrospective registration may choose to
alert their readers by publishing an additional “prospective” or
“retrospective” registration note, along with the registration number and
the name of trial registry.

We propose that CONSORT requires such the precision in its
explanatory document.

References

1. Schulz KF, Altman DG, Moher D, for the CONSORT Group. CONSORT 2010
Statement: updated guidelines for reporting parallel group randomised
trials. BMJ 2010;340:c332

2. Received from the Australian New Zealand Clinical Trials Registry
(ANZCTR http://www.anzctr.org.au). Sydney (NSW): The University of Sydney
(Australia); 29 October 2009.

Competing interests:
None declared

Competing interests: No competing interests

25 March 2010
Ludovic Reveiz
Associate Researcher
Karmela Krleža-Jeriæ. Canadian Institutes of Health Research (CIHR), Ottawa, ON, Canada
Instituto de Investigaciones Sanitas, Colombian Cochrane Center, Bogota, Colombia