Clinical Trial Registration in Physical Therapy Journals: Recommendations from the International Society of Physiotherapy Journal Editors

How Common Is Clinical Trial Registration?

The first major register for health care trials was established in 1998.⁴ Although thousands of trials were soon registered, the majority of trials remained unregistered. In 2004, clinical trial registration was endorsed by the International Committee of Medical Journal Editors (ICMJE).⁴ In addition to endorsing clinical trial registration, member journals of the ICMJE made prospective registration compulsory for all clinical trials that commenced participant recruitment after July 1, 2005.⁴ Many other journals also endorsed clinical trial registration, and the number of registered trials increased rapidly.⁵ Since then, many organizations have added their support for clinical trial registration. For example, in 2008 the World Medical Association included a new item on the Declaration of Helsinki stating that “Every clinical trial must be registered in a publicly accessible database before recruitment of the first subject.”⁶ Some ethics committees have made trial registration a condition of ethical approval.

Although some physical therapy journals also have encouraged clinical trial registration,^7–9 only about 6% of the randomized trials investigating the effects of physical therapy interventions published in 2009 had been registered prospectively.¹⁰ In an attempt to rectify this situation, this editorial recommending prospective registration has been co-authored by several members of the International Society of Physiotherapy Journal Editors (ISPJE). The remainder of the editorial will: define which trials should be registered; explain how researchers can register their trials; announce tougher policies about clinical trial registration that are being adopted by some member journals of the ISPJE; and identify who can contribute to ensuring that clinical trial registration achieves its potential benefits.

Which Trials Should Be Registered?

Any clinical trial should be prospectively registered before the first participant is recruited into the study. The World Health Organization (WHO) defines clinical trials as “any research study that prospectively assigns human participants or groups of humans to one or more health-related interventions to evaluate the effects on health outcomes.”¹¹

How Can I Register My Trial?

Clinical trial registration should be quick, easy, and free of charge. Many clinical trial registries have been established, including some that focus on a particular disease (eg, Internet Stroke Center Trials Registry, www.strokecenter.org/trials) or geographical region (eg, Pan African Clinical Trials Registry, www.pactr.org). Researchers often choose to register their trials in their country's national register, although this is not compulsory. It is more important that researchers choose a registry that elicits and documents all the relevant content from the original protocol (outlined below) and that has satisfactory quality, validity, accessibility, unique identification, technical capacity, and administration. To assist researchers, WHO maintains a list of registries that meet these criteria (http://www.who.int/ictrp/network/primary/en/index.html). Currently 16 registries are listed. Among these, researchers could choose one that processes applications swiftly or that allows communication using their native language.

When registering their protocol, researchers will be asked to provide information such as descriptions of the intervention(s) and comparison(s) studied, study hypotheses, primary and secondary outcomes, eligibility criteria, sample size, blinding, funding, principal investigators, and dates of commencement and anticipated completion of the study. It is common for trial registries to review the information for completeness and clarity, so some editing might be needed. The registry will then provide a unique trial registration number to the researchers. This number should be included in all reports of the trial's results as a link to the registered protocol for editors, reviewers, and readers.

Prospective registration can be done any time before the first participant is recruited. Many researchers wait until immediately before recruitment starts, so that any late changes to the protocol (such as alterations requested by an ethics committee) do not necessitate an amendment to the registry entry. Although not ideal, protocol amendments are sometimes made after recruitment starts. These should be updated on the registered protocol as well. The trial registry will publicly document what changed and on what date.

ISPJE Member Journals Introducing Mandatory Prospective Registration Policies

The executive of the ISPJE strongly recommends that member journals adopt a policy of mandatory prospective registration for all clinical trials. Several member journals are implementing such policies. Physical Therapy has already implemented a policy of mandatory prospective clinical trial registration, which applies to trials that commenced participant recruitment after January 1, 2009. The Table lists other member journals and their nominated dates to implement mandatory prospective clinical trial registration, as well as the trials that this policy applies to (based on the commencement date of participant recruitment).

Who Else Can Help Ensure Clinical Trial Registration Achieves Its Potential Benefits?

In addition to the recommendations for researchers and editorial boards outlined above, others can contribute to ensuring that clinical trial registration achieves its potential benefits. Everyone in the profession can ensure that their colleagues are aware of clinical trial registration and its importance. Educators should ensure that the research component of physical therapy training programs explains the importance of trial registration. Clinicians also can advise or help patients to search trial registers to identify relevant trials for which the patient might volunteer. Administrators of clinical trial registries that do not meet the WHO criteria can strive to attain this status. Grant review panels can make funding contingent on prospective registration for proposed clinical trials. More ethics review committees can make their approval of trials contingent upon prospective registration as well. However, even universal prospective registration may make no difference to selective reporting and publication bias unless there is an expectation that protocols will be compared to published reports before publication. Therefore, journal editors and peer reviewers must remember to check for discrepancies between submitted manuscripts and registry entries.

Physical therapy clinical trials that are conducted and reported according to a pre-specified protocol are more likely to provide credible information than those that do not. Prospective clinical trial registration is therefore of great potential value to the clinicians, consumers, and researchers who rely on clinical trial data, and that is why ISPJE is recommending that members enact a policy for prospective trial registration.