Registration of trials is essential to ensure all results are publicly available and that ethical obligations to participants are met. Recent evidence of selective reporting of results has eroded public and academic confidence in publications of clinical trials, leading to renewed calls for trial registration. The rationale for registering trials is well known (Box 1). Most importantly, the contribution to social good that justifies research on human participants is not realized when resulting knowledge remains invisible.
The Canadian Institutes of Health Research hosted an open meeting on 4 October 2004 in Ottawa, Canada, to foster international consensus on trial registration. The resulting Ottawa statement issued by the International Committee of Medical Journal Editors (ICMJE) aims to establish internationally recognized principles for registration (1, 2) as a follow-on to the Trials Registration Policy issued in 2004 (3).
Summary of principles
The mandatory registration of all trials has three components:
• Obtaining an internationally unique identification number (unique ID)
• Registering the original protocol along with subsequent amendments
• Registering the trial results.
Key principles Registering all types of trials: Protocol information and results from all trials related to health or healthcare - regardless of topic, design, outcomes, or market status of interventions exam-ined-should be registered and publicly available.
Timing of public release of protocol information: The public should have cost-free access to the Unique ID, minimum protocol items, and consent forms prior to participant enrolment. Registered amendments should be made publicly available as they occur.
Box 1: Rationale for registration of clinical trials
• Respect the investigator-participant covenant to contribute to biomedical knowledge by making trial methods and results public
• Provide global open access to information
• Reduce unnecessary duplication of invested research resources through awareness of existing trials
• Assure accountability with regard to global standards for ethical research
• Enable monitoring of adherence to ethical principles and process
• Increase the reliability and availability of evidence on which healthcare decisions are based
• Improve trial participation
• Increase opportunities for collaboration
• Ensure transparency of trial design and methods
• Provide open review of protocols to improve trial quality and refine methods
• Provide means for identification and prevention of biased under-reporting or over-reporting of research
• Accelerate knowledge creation
Registering unpublished results: At a minimum, results for outcomes and analyses specified in the protocol (as approved by the institutional review boards/independent ethics committees) as well as data on harms, should be registered regardless of whether or not they are published.
1. Krleza-Jeric, K, Chan, A., Dickersin, K. et al. Principles for international registration of protocol information and results from human trials of health related interventions: Ottawa statement (part 1). British Medical Journal, 330: 956-958 (2005). http://www.bmj.com
2. De Angelis, C., Drazen, J.M., Frizelle, F.A. et al. Clinical trial registration: a statement from the International Committee of Medical Journal Editors. Annals of Internal Medicine, 141: 477-478. (2004) and http://www.icmje.org
3. Selective reporting and clinical trial registration &Trials registration policy. WHO Drug Information, Volume 18, Number 4, page 278-280 (2004).