Example

 

“This study was registered in the Iranian Registry of Clinical Trials under the code IRCT20150531022498N30: https://en.irct.ir/trial/41031. Registered on July 26, 2019.”[47]

 

Explanation

The consequences of non-publication of entire trials (ie, publication bias), [48-50] and of selective reporting of outcomes and analyses within trials, have been well documented [51-53]. For almost 40 years, there have been growing calls to address these practices. Today, a ubiquitous view recommends trial registration as the best practice to achieve this goal, and inform policymakers and potential participants about ongoing trials. Registering clinical trials, before any assignment of participants, with unique trial identification numbers and other basic information about the trial so that essential details are made publicly available, is a minimum best practice [54-57]. Serious problems of withholding data [58] led to renewed efforts to ensure registration of randomised trials. The World Health Organization (WHO) states that “the registration of all interventional trials is a scientific, ethical and moral responsibility” [59]

 

In September 2004, the ICMJE established a policy that it would only consider trials for publication if they had been registered before the enrolment of the first participant [60]. This policy resulted in a substantial increase in the number of trials being registered [61]. However, some trials are still not registered [49]. The ICMJE gives guidance on acceptable registries (https://www.icmje.org/about-icmje/faqs/clinical-trials-registration/) and also accepts registration in WHO primary registries (https://www.who.int/clinical-trials-registry-platform/network/primary-registries) and ClinicalTrials.gov. Registers charging a fee to view their content should be avoided to ensure equity of access for everyone, including patients and the public.

 

The Transparency and Openness Promotion (TOP) guidelines, endorsed and used by thousands of journals, recommends trial registration [62]. In a survey of 168 high impact factor medical journals’ “Instructions to authors” in 2014, 78 journals stated that all recent clinical trials must be registered as a requirement of submission to that journal [63]. A more recent survey in 2019 of surgical journals publishing randomised trials found that 53 of 82 journals mandated prospective registration [64].

 

Despite recommendations, and mandates in some jurisdictions for clinical trialists to register their trial and evidence that registration deters selective reporting, this is still not happening universally [65 66]. Authors should provide the name of the registry, the trial’s associated registration number, date of registration and, where possible, the URL for the trial’s registration. We recommend that authors also report whether (or when) the trial results are available on the associated trial register.

 

Despite the considerable increase in clinical trial registration, there is a strong body of evidence showing the lack of access to trial results [67-70]. The latest version of the Declaration of Helsinki states that “Researchers have a duty to make publicly available the results of their research on human participants and are accountable for the timeliness, completeness, and accuracy of their reports . . . Negative and inconclusive as well as positive results must be published or otherwise made publicly available.” In 2015, WHO published a new statement on the public disclosure of trial results, which requests that “the key outcomes are to be made publicly available within 12 months of study completion by posting to the results section of the primary clinical trial registry. Where a registry is used without a results database available, the results should be posted on a free-to-access, publicly available, searchable institutional website of the Regulatory Sponsor, Funder or Principal Investigator.” Some legislations are also in place in the US, UK, and Europe requesting the posting of trial results on clinical trials registry within 12 months after study completion [71-73].

 

Authors should indicate whether the trial results are publicly posted to the trial registry, as a preprint (with URL citation) or as published articles (with citations).