Clinical Trials and Research Registration

The journal supports prospective and transparent registration of medical research involving human participants as an important safeguard against selective reporting, undisclosed outcome changes, unnecessary duplication, and distortion of the scientific record.

In accordance with the World Medical Association Declaration of Helsinki (2024), medical research involving human participants should be registered in a publicly accessible database before recruitment of the first participant. The journal also follows the current ICMJE Recommendations, updated January 2026, concerning prospective clinical trial registration.

Clinical Trials

For the purposes of this policy, a clinical trial includes research that prospectively assigns individual participants or groups of participants to one or more health-related interventions to evaluate effects on health outcomes.

Health-related interventions may include, among others:

  • medicines and other therapeutic interventions;
  • surgical procedures;
  • medical devices;
  • behavioral interventions;
  • dietary interventions;
  • educational programs;
  • quality-improvement interventions;
  • changes in processes of care.

Clinical trial registration requirements apply regardless of whether the trial is commercially sponsored, investigator initiated, single-centre or multicentre, and regardless of whether the intervention is pharmacological or non-pharmacological.

ICMJE uses this broad definition and requires prospective registration of clinical trials.

Prospective Registration

Clinical trials must be registered before recruitment of the first participant and, for purposes of ICMJE-compliant trial registration, at or before the time of the first participant’s consent for enrollment.

Ethics committee or IRB approval does not substitute for trial registration. Ethical approval and public registration are separate requirements.

Registration performed only after recruitment has begun is considered retrospective registration and does not fulfil the normal purpose of prospective registration.

Failure to prospectively register a clinical trial may make the manuscript ineligible for consideration. Any exceptional circumstance must be fully explained to the journal. An exception, if considered at all, should be rare, transparent, and subject to editorial assessment; subsequent registration does not erase the original failure to register prospectively.

Acceptable Trial Registries

Clinical trials should be registered in a publicly accessible registry acceptable under ICMJE standards, including:

  • a primary registry participating in the WHO International Clinical Trials Registry Platform (ICTRP); or
  • ClinicalTrials.gov.

The registration must be publicly accessible and sufficiently complete and informative. ICMJE requires an acceptable registry record to contain the applicable minimum trial-registration dataset; registrations containing missing or uninformative mandatory fields may be considered inadequate.

Registration solely in a non-qualifying or non-public system may not satisfy the journal’s requirements.

Accuracy and Updating of Registry Information

The information in the registry must accurately reflect the study protocol.

Authors are responsible for maintaining the trial record and updating it appropriately when legitimate changes occur.

Material changes to items such as:

  • study design;
  • participant eligibility;
  • intervention;
  • primary or secondary outcomes;
  • sample size;
  • recruitment status;
  • study completion;
  • data-sharing plans, where applicable,

should be updated transparently in the registry according to applicable requirements.

Outcome definitions or other important trial information must not be changed retrospectively for the purpose of making study findings appear more favorable.

Material discrepancies between the registry, protocol, and submitted manuscript must be explained to the journal.

ICMJE places responsibility on authors to explain discrepancies between information or results reported in registries and those reported in journal publications.

Registration Information in the Manuscript

Manuscripts reporting clinical trials must clearly provide the:

  • name of the trial registry;
  • registration number or unique trial identifier;
  • relevant registration status or date when necessary to assess prospective registration.

The journal recommends that the trial registration number be included at the end of the abstract, consistent with ICMJE guidance.

Authors must not provide a registration number belonging to a different study, an earlier version of an unrelated protocol, or another trial in a manner that creates a false impression of prospective registration.

Secondary Analyses of Registered Trials

A secondary analysis of data from a previously registered parent clinical trial should identify and cite the registration number of the original trial.

ICMJE states that secondary analyses of primary clinical trials should not normally be registered as separate clinical trials merely because a new analysis is being performed; instead, they should refer to the parent trial registration.

The manuscript must clearly identify the work as a secondary analysis and explain how it differs from previously reported analyses.

Non-Trial Research

Purely observational research is not classified as a clinical trial under the ICMJE definition because the researcher does not assign the health-related intervention. ICMJE therefore encourages, but does not require under its clinical-trial policy, registration of non-trial research.

However, authors must also take account of the broader Declaration of Helsinki 2024 principle that medical research involving human participants should be publicly registered before recruitment of the first participant, where that requirement is applicable to the study design.

Applicable national, institutional, funder, or regulatory registration requirements must also be followed.

Pediatric Clinical Trials

The same principles of prospective registration apply to trials involving newborns, infants, children, and adolescents.

A pediatric trial is not exempt from registration merely because it:

  • involves a small number of participants;
  • is conducted at a single institution;
  • is investigator initiated;
  • evaluates a behavioral, nutritional, educational, device, surgical, or process-of-care intervention rather than a medicine;
  • is described as a pilot or feasibility study but otherwise meets the definition of a clinical trial.

Prospective registration is particularly important in pediatric research because small populations and limited evidence bases can increase the consequences of selective reporting or unnecessary duplication of research.

Data Sharing Information

Clinical trial registration and reporting should also comply with applicable ICMJE requirements concerning data-sharing information.

Under current ICMJE policy, trials beginning participant enrollment on or after 1 January 2019 must include a data-sharing plan in the trial registration, and manuscripts reporting clinical trials are expected to include an appropriate data-sharing statement.

Detailed requirements are provided in the journal’s Research Data Policy.

Journal Assessment

The journal may verify the trial registry record and compare it with the manuscript, protocol, reported outcomes, recruitment dates, and other relevant information.

The journal may request clarification concerning:

  • missing or delayed registration;
  • retrospective registration;
  • changes to primary or secondary outcomes;
  • discrepancies in sample size or study design;
  • unexplained changes to recruitment or intervention details;
  • use of an inappropriate or non-public registry;
  • inconsistencies between registered and published results.

Suspected manipulation or falsification of trial-registration information, undisclosed outcome switching, or intentional misrepresentation of prospective registration may lead to rejection or action under the journal’s Research Misconduct, Editorial Actions, and Corrections and Retractions policies.

Detailed requirements concerning clinical trial conduct, protocol transparency, reporting, data sharing, safety, and post-trial responsibilities are provided in the journal’s separate Clinical Trials Policy.

ISSN 2181-3353 (Print)
ISSN 2181-3353 (Online)