CONSORT 2025 statement: updated guideline for reporting randomised trials — TEI-tagged view

Sally HopewellpersName, An‐Wen ChanpersName, Professor Gary S. CollinspersName, Asbjørn HróbjartssonpersName, David MoherpersName, Kenneth F. SchulzpersName, R. TunnpersName, Rakesh AggarwalpersName, Michael BerkwitspersName, Jesse A. BerlinpersName, Nita BhandaripersName, Nancy J. ButcherpersName, Marion CampbellpersName, Runcie C.W. ChidebepersName, Diana ElbournepersName, Andrew FarmerpersName, Dean FergussonpersName, Robert M. GolubpersName, Steven N. GoodmanpersName, Tammy HoffmannpersName, John P. A. IoannidispersName, Brennan C KahanpersName, Rachel L KnowlespersName, Sarah E LambpersName, Steff LewispersName, Elizabeth LoderpersName, Martin OffringapersName, Philippe RavaudpersName, Dawn P. RichardspersName, Frank W. RockholdpersName, David L. SchrigerpersName, Nandi SiegfriedpersName, Sophie StaniszewskapersName, R. TaylorpersName, Lehana ThabanepersName, David TorgersonpersName, Sunita VohrapersName, Ian R. WhitepersName, Isabelle BoutronpersName (2025date). “CONSORT 2025 statement: updated guideline for reporting randomised trials.” BMJtitle·j.

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Abstract. Abstract Background Well designed and properly executed randomised trials are considered the most reliable evidence on the benefits of healthcare interventions. However, there is overwhelming evidence that the quality of reporting is not optimal. The CONSORTterm·dom (Consolidated Standards of Reporting Trials) statement was designed to improve the quality of reporting and provides a minimum set of items to be included in a report of a randomised trial. CONSORTterm·dom was first published in 1996, then updated in 2001 and 2010. Here, we present the updated CONSORTterm·dom 2025 statement, which aims to account for recent methodological advancements and feedback from end users. Methods We conducted a scoping review of the literature and developed a project-specific database of empirical and theoretical evidence related to CONSORTterm·dom, to generate a list of potential changes to the checklist. The list was enriched with recommendations provided by the lead authors of existing CONSORTterm·dom extensions (Harms, Outcomes, Non-pharmacological Treatment), other related reporting guidelines (TIDieR) and recommendations from other sources (eg, personal communications). The list of potential changes to the checklist was assessed in a large, international, online, three-round Delphi survey involving 317 participants and discussed at a two-day online expert consensusterm·mth meeting of 30 invited international experts. Results We have made substantive changes to the CONSORTterm·dom checklist. We added seven new checklist items, revised three items, deleted one item, and integrated several items from key CONSORTterm·dom extensions. We also restructured the CONSORTterm·dom checklist, with a new section on open science. The CONSORTterm·dom 2025 statement consists of a 30-item checklist of essential items that should be included when reporting the results of a randomised trial and a diagram for documenting the flow of participants through the trial. To facilitate implementation of CONSORTterm·dom 2025, we have also developed an expanded version of the CONSORTterm·dom 2025 checklist, with bullet points eliciting critical elements of each item. Conclusion Authors, editors, reviewers, and other potential users should use CONSORTterm·dom 2025 when writing and evaluating manuscripts of randomised trials to ensure that trial reports are clear and transparent. Introduction “Readers should not have to infer what was probably done; they should be told explicitly.” Douglas G Altman 1 Randomised trials, when appropriately designed, conducted, analysed, and reported, are generally considered the highest quality evidence in evaluating healthcare interventions. Critical appraisal of the quality of randomised trials is possible only if their design, conduct, analysis, and results are thoroughly and accurately reported. To interpret a trial accurately, readers need complete and transparent information on its methods and findings. However, extensive evidence displays that the completeness of reporting of randomised trials is inadequate 2 3 and that incomplete reporting may be associated with biased estimates of intervention effects. 4 Similarly, having a clear and transparent trial protocol is important because it prespecifies the methods used in the trial, such as the primary outcome, thereby reducing the likelihood of undeclared post hoc changes. 5 Efforts to improve the reporting of randomised trials gathered impetus in the early 1990s and resulted in the Standardised Reporting of Trials (SORT) and Asilomar initiatives in 1994. Those initiatives then led to publication of the CONSORTterm·dom (Consolidated Standards of Reporting Trials) statement in 1996, 6 revised in 2001 7 with an accompanying explanation and elaboration document. 8 CONSORTterm·dom was then updated in 2010, 9 along with an updated explanation and elaboration article. 10 Similar problems related to the lack of complete and transparent reporting of trial protocols led to the development of the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) statement, published in 2013, 11 and its accompanying explanation and elaboration document 12 explaining the principles underlying the statement. CONSORTterm·dom is endorsed by numerous journals worldwide and by prominent editorial organisations, including the World Association of Medical Editors (WAME), International Committee of Medical Journal Editors (ICMJE) and Council of Science Editors (CSE). The introduction of CONSORTterm·dom within journals has been shown to be associated with improved quality of reports of randomised trials. Some evidence shows that journal endorsement of CONSORTterm·dom is associated with better reporting and that reporting is improving over time. 2 13 14 15 A Cochrane review of 50 evaluations of 16 604 trials assessed the association between journals’ endorsement of CONSORTterm·dom and the reporting of trials they published; 25 of 27 CONSORTterm·dom checklist items were more completely reported when a trial was published in a CONSORTterm·dom endorsing as opposed to non-endorsing journal. 2 14 However, a causal effect cannot be proven. At a minimum, CONSORTterm·dom has sensitised many end users (eg, authors, journal editors, and peer reviewers) to how important careful and thorough reporting can be for randomised trials. SPIRIT and CONSORTterm·dom are evidence based guidelines that comprise a checklist of essential items that should be included in protocols and primary reports of completed randomised trials, respectively, and a diagram that documents the flow of participants through a trial. These statements provide guidance to authors on the minimum information that should be included in the reporting of trials to ensure that trial protocols and trial reports are clear and transparent. They are published alongside explanation and elaboration documents, which provide the meaning and rationale for each checklist item, examples of good reporting, and relevant empirical evidence where possible. In January 2020, the SPIRIT and CONSORTterm·dom executive groups met in Oxford, UK. As the SPIRIT and CONSORTterm·dom statements are conceptually linked, with overlapping content and similar dissemination and implementation strategies, the two groups decided it was more effective to work together and formed one group. Summary points To interpret a randomised trial accurately, readers need complete and transparent information on its methods and findings The CONSORTterm·dom 2025 statement provides updated guidance for reporting the results of randomised trials, that reflects methodological advancements and feedback from end users The CONSORTterm·dom 2025 statement consists of a 30-item checklist of essential items, a diagram for documenting the flow of participants through the trial, and an expanded checklist that details the critical elements of each checklist item Authors, editors, reviewers, and other potential users should use CONSORTterm·dom 2025 when writing and evaluating manuscripts of randomised trials to ensure that trial reports are clear and transparent Decision to update the SPIRIT and CONSORTterm·dom statements SPIRIT and CONSORTterm·dom are living guidelines and it is vital that the statements are periodically updated to reflect new evidence, methodological advancements, and feedback from users; otherwise, their value and usefulness will diminish over time. 16 Updating the SPIRIT 2013 and CONSORTterm·dom 2010 statements together was also an opportunity to further align both checklists and to provide users with consistent guidance in the reporting of trial design, conduct, analysis, and results from trial protocol to final publication. Harmonising the reporting process should improve usability and adherence, and lead to more-complete reporting. 17 Here, we introduce the updated CONSORTterm·dom 2025 statement; the updated SPIRIT 2025 statement is published separately. 18 Development of CONSORTterm·dom 2025 The methods used to update the CONSORTterm·dom statement followed the EQUATOR Network guidance for developers of health research guidelines 19 and have been described in detail elsewhere. 20 21 In brief, we first conducted a scoping review of the literature to identify published comments suggesting modifications and additions or reflecting on strengths and challenges of CONSORTterm·dom 2010, the findings of which have been published separately. 22 We also developed a project specific database (SCEBdb) for empirical and theoretical evidence related to CONSORTterm·dom and risk of bias in randomised trials. 23 The evidence identified in the scoping review was combined with evidence from, and recommendations provided by the lead authors of, certain key existing CONSORTterm·dom extensions whose checklist items apply to all trials (Harms, 24 Outcomes 25 ), or a considerable number of trials 26 (Non-pharmacological Treatment 27 ), other related reporting guidelines (the template for intervention description and replication (TIDieR) 28 ), and recommendations from other sources (eg, personal communications). Using the existing CONSORTterm·dom 2010 checklist as the starting point, a list of potential modifications or additions to the checklists was then created using the gathered evidence from the scoping review and recommendations. This list of potential changes was presented to end users for feedback in a large international online Delphi survey, involving 317 participants who responded to round 1, 303 to round 2 and 290 to round 3. Delphi participants were identified through existing SPIRIT and CONSORTterm·dom collaborations, and professional research networks and societies. Participants were also recruited via an expression of interest form on the SPIRIT-CONSORT update project website. A broad range of end user roles were represented, the most frequent being statisticians/methodologists/epidemiologists (n=198), systematic reviewers/guideline developers (n=73), trial investigators (n=73), clinicians (n=58), journal editors (n=47), and patient representatives (n=17) (numbers not mutually exclusive). During the three-round Delphi survey, participants were asked to rate on a 5-point Likert scale the extent to which they agreed with the inclusion of each item in the updated CONSORTterm·dom checklist. Free text boxes were provided for comments on each item and to suggest additional new checklist items. The Delphi survey results were then presented and discussed at a two-day online expert consensusterm·mth meeting via Zoom, on 1 and 2 March 2023, attended by 30 invited international participants representing the different stakeholder groups included in the Delphi survey. During the meeting, each new and modified CONSORTterm·dom checklist item was discussed and agreement sought. An anonymous poll via Zoom was used to help establish the level of support for items where the discussion indicated differing opinions; these polls were advisory and no formal consensus threshold was specified. After the expert consensusterm·mth meeting, the executive group held a two-day, in-person writing meeting in Oxford on 25 and 26 April 2023, where the format and wording of each new or modified CONSORTterm·dom checklist item was reviewed and agreed on. The draft checklist was then circulated to consensus meeting participants to confirm whether they represented the group consensus or needed clarification. CONSORTterm·dom items were further revised by the executive group in response to this feedback. The finalised items address the minimum content for inclusion in a trial report, although that should not deter prospective authors from including additional information that they deem important or that facilitates replication. Members of the executive group and the 30 invited consensus meeting participants are authors of the manuscript and their names are listed at the end of the manuscript. Main changes to CONSORTterm·dom 2025 We have made a number of substantive changes to the CONSORTterm·dom 2025 checklist (see box 1 ). We have added seven new checklist items, revised three items, deleted one item, and integrated several items from key CONSORTterm·dom extensions (Harms, 24 Outcomes, 25 Non-pharmacological Treatment 27 ) and other related reporting guidelines (TIDieR 28 ). We also restructured the CONSORTterm·dom checklist, with a new section on open science, which includes items that are conceptually linked, such as trial registration (item 2), where the trial protocol and statistical analysis plan can be accessed (item 3), sharing of de-identified participant level data (item 4), and funding and conflicts of interest (item 5). We have also harmonised the wording between CONSORTterm·dom and SPIRIT checklist items and clarified and simplified the wording of some items. For a detailed comparison of the changes made in the CONSORTterm·dom 2025 checklist from CONSORTterm·dom 2010, see appendix 1. We have also updated the CONSORTterm·dom explanation and elaboration document, 29 which has been extensively revised and describes the rationale and scientific background for each CONSORTterm·dom 2025 checklist item and provides published examples of good reporting. Box 1 Summary of main changes in CONSORTterm·dom 2025 Addition of new checklist items Item 4: added item on data sharing, including where and how individual de-identified participant data, statistical code, and any other materials can be accessed. Item 5b: added item on financial and other conflicts of interest of manuscript authors. Item 8: added item on how patients and/or the public were involved in the design, conduct, and/or reporting of the trial. Item 12b: added item on eligibility criteria for sites and for individuals delivering the interventions, where applicable Item 15: added item on how harms and other unintended effects were assessed. Item 21: added items to define who is included in each analysis (eg, all randomised participants) and in which group (item 21b), and how missing data were handled in the analysis (item 21c). Item 24: added item on intervention delivery, including how the intervention and comparator were actually administered (item 24a) and details of concomitant care received during the trial (item 24b). Completely revised checklist items Item 3: revised item to include where the statistical analysis plan can be accessed in addition to the trial protocol. Item 10: revised item to include reporting of important changes to the trial after it commenced, including any outcomes or analyses that were not prespecified. Item 26: revised item to specify for each primary and secondary outcome—the number of participants included in the analysis and the number of participants with available data at each time point for each treatment group. Deletion of checklist item Deleted item on generalisability of trial findings, which is now incorporated under trial limitations (item 30). Integration of checklist items from key CONSORTterm·dom extensions Addition of items related to reporting of how harms 24 were assessed and analysed (items 7, 15, 21a, 23a, 27), how outcomes 25 were measured and analysed (items 14, 26), and how the intervention 27 28 and comparator were actually administered and by whom (item 24). Structure and organisation of checklist items Restructuring of checklist, with a new section on open science, which includes items that are conceptually linked such as trial registration (item 2), where the trial protocol and statistical analysis plan can be accessed (item 3), sharing of de-identified participant level data (item 4), and funding and conflicts of interest (item 5). Aligned wording of some CONSORTterm·dom checklist items with that of SPIRIT checklist items and vice versa. Clarified and simplified wording of some items. To help facilitate implementation of CONSORTterm·dom 2025, we have also developed an expanded version of the CONSORTterm·dom 2025 checklist, with bullet points eliciting critical elements of each item. This is similar to the model proposed by the COBWEB (CONSORT-based web tool) 30 and COBPeer (CONSORTterm·dom based peer review tool) 31 studies and used in the 2020 PRISMA guidance for reporting systematic reviews. 32 The expanded checklist comprises an abridged version of elements presented in the CONSORTterm·dom 2025 explanation and elaboration document, 29 with examples and references removed (see appendix 2). Scope of CONSORTterm·dom 2025 The CONSORTterm·dom 2025 statement comprises a 30-item checklist and provides a minimum set of items to be included in a report of a randomised trial ( table 1 ) and a diagram for documenting the flow of participants through a trial ( fig 1 ). We strongly recommend the CONSORTterm·dom 2025 statement be used alongside the CONSORTterm·dom 2025 explanation and elaboration document. 29 The CONSORTterm·dom 2025 statement supersedes the CONSORTterm·dom 2010 statement, which should no longer be used. Journal editors and publishers should update their instructions to authors to refer to CONSORTterm·dom 2025. CONSORTterm·dom 2025 provides guidance for reporting all randomised trials but focuses on the most common type, the two-group parallel design. Table 1 CONSORTterm·dom 2025 checklist of information to include when reporting a randomised trial Section/topic No CONSORTterm·dom 2025 checklist item description Title and abstract Title and structured abstract 1a Identification as a randomised trial 1b Structured summary of the trial design, methods, results, and conclusions Open science Trial registration 2 Name of trial registry, identifying number (with URL) and date of registration Protocol and statistical analysis plan 3 Where the trial protocol and statistical analysis plan can be accessed Data sharing 4 Where and how the individual de-identified participant data (including data dictionary), statistical code and any other materials can be accessed Funding and conflicts of interest 5a Sources of funding and other support (eg, supply of drugs), and role of funders in the design, conduct, analysis and reporting of the trial 5b Financial and other conflicts of interest of the manuscript authors Introduction Background and rationale 6 Scientific background and rationale Objectives 7 Specific objectives related to benefits and harms Methods Patient and public involvement 8 Details of patient or public involvement in the design, conduct and reporting of the trial Trial design 9 Description of trial design including type of trial (eg, parallel group, crossover), allocation ratio, and framework (eg, superiority, equivalence, non-inferiority, exploratory) Changes to trial protocol 10 Important changes to the trial after it commenced including any outcomes or analyses that were not prespecified, with reason Trial setting 11 Settings (eg, community, hospital) and locations (eg, countries, sites) where the trial was conducted Eligibility criteria 12a Eligibility criteria for participants 12b If applicable, eligibility criteria for sites and for individuals delivering the interventions (eg, surgeons, physiotherapists) Intervention and comparator 13 Intervention and comparator with sufficient details to allow replication. If relevant, where additional materials describing the intervention and comparator (eg, intervention manual) can be accessed Outcomes 14 Prespecified primary and secondary outcomes, including the specific measurement variable (eg, systolic blood pressure), analysis metric (eg, change from baseline, final value, time to event), method of aggregation (eg, median, proportion), and time point for each outcome Harms 15 How harms were defined and assessed (eg, systematically, non-systematically) Sample size 16a How sample size was determined, including all assumptions supporting the sample size calculation 16b Explanation of any interim analyses and stopping guidelines Randomisation: Sequence generation 17a Who generated the random allocation sequence and the method used 17b Type of randomisation and details of any restriction (eg, stratification, blocking and block size) Allocation concealment mechanism 18 Mechanism used to implement the random allocation sequence (eg, central computer/telephone; sequentially numbered, opaque, sealed containers), describing any steps to conceal the sequence until interventions were assigned Implementation 19 Whether the personnel who enrolled and those who assigned participants to the interventions had access to the random allocation sequence Blinding 20a Who was blinded after assignment to interventions (eg, participants, care providers, outcome assessors, data analysts) 20b If blinded, how blinding was achieved and description of the similarity of interventions Statistical methods 21a Statistical methods used to compare groups for primary and secondary outcomes, including harms 21b Definition of who is included in each analysis (eg, all randomised participants), and in which group 21c How missing data were handled in the analysis 21d Methods for any additional analyses (eg, subgroup and sensitivity analyses), distinguishing prespecified from post hoc Results Participant flow, including flow diagram 22a For each group, the numbers of participants who were randomly assigned, received intended intervention, and were analysed for the primary outcome 22b For each group, losses and exclusions after randomisation, together with reasons Recruitment 23a Dates defining the periods of recruitment and follow-up for outcomes of benefits and harms 23b If relevant, why the trial ended or was stopped Intervention and comparator delivery 24a Intervention and comparator as they were actually administered (eg, where appropriate, who delivered the intervention/comparator, how participants adhered, whether they were delivered as intended (fidelity)) 24b Concomitant care received during the trial for each group Baseline data 25 A table showing baseline demographic and clinical characteristics for each group Numbers analysed, outcomes and estimation 26 For each primary and secondary outcome, by group: ● the number of participants included in the analysis ● the number of participants with available data at the outcome time point ● result for each group, and the estimated effect size and its precision (such as 95% confidence interval) ● for binary outcomes, presentation of both absolute and relative effect size Harms 27 All harms or unintended events in each group Ancillary analyses 28 Any other analyses performed, including subgroup and sensitivity analyses, distinguishing pre-specified from post hoc Discussion Interpretation 29 Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence Limitations 30 Trial limitations, addressing sources of potential bias, imprecision, generalisability, and, if relevant, multiplicity of analyses Fig 1 CONSORTterm·dom 2025 flow diagram. Flow diagram of the progress through the phases of a randomised trial of two groups (ie, enrolment, intervention allocation, follow-up, and data analysis). CONSORTterm·dom=Consolidated Standards of Reporting Trials Extensions to CONSORTterm·dom have been developed to tackle the methodological issues associated with reporting different types of trial designs, data, and interventions. Examples of extensions for trial designs include recommendations for adaptive designs, 33 cluster trials, 34 crossover trials, 35 early phase trials, 36 factorial trials, 37 non-inferiority and equivalence trials, 38 pragmatic trials, 39 multi-arm trials, 40 n-of-1 trials, 41 pilot and feasibility trials, 42 and within-person trials. 43 Other extensions include non-pharmacological treatments, 27 outcomes, 25 patient reported outcomes, 44 surrogate outcomes, 45 social and psychological interventions, 46 harms, 24 abstracts, 47 and health equity. 48 We will engage with the leaders of these extensions to implement a process for aligning them with the updated CONSORTterm·dom 2025 statement. In the meantime, we recommend that readers use the existing version of the relevant CONSORTterm·dom extension(s). Implication and limitations The objective of the CONSORTterm·dom 2025 statement is to provide a minimum set of recommendations to authors about the content they should include in order to report their trials in a clear, complete, and transparent manner. 9 10 Readers, peer reviewers, clinicians, guideline writers, patients and the public, and editors can also use CONSORTterm·dom 2025 to help them appraise the reporting of randomised trials. We also strongly recommend the submission of a completed CONSORTterm·dom 2025 checklist as part of the manuscript submission process, detailing where in the manuscript checklist items are reported, and uploaded as part of the supplementary materials. 49 An explicit description of what was done and what was found, without ambiguity or omission, best serves the interests of all readers. 9 It is important to note that CONSORTterm·dom 2025 and SPIRIT 2025 do not include recommendations for designing, conducting, or analysing trials, but nevertheless the recommendations contained here can help researchers in the design, conduct, and analysis of their trial by highlighting key issues to consider. Updating the SPIRIT and CONSORTterm·dom statements together was also an opportunity to align reporting in both checklists and to provide users with consistent guidance in the reporting of trial design, conduct, and analysis, from the trial protocol to final publication. 17 Thus, clear and transparent reports of trial protocols should in turn facilitate properly designed and well conducted trials. In addition, transparent reporting of trial results can reveal deficiencies in research if they exist and allow better estimates of their prevalence and severity. Importantly, however, CONSORTterm·dom 2025 is not meant to be used as a quality assessment instrument. Rather, the content of CONSORTterm·dom 2025 focuses on reporting items related to the internal and external validity of randomised trials. With CONSORTterm·dom 2025, we do not suggest a rigid structure for the reporting of randomised trials. Instead, the format of articles should abide by the journal’s individual style and its “Instructions to Authors.” Authors should address checklist items somewhere in the article, with sufficient detail and clarity. 9 We also promote the use of additional online supplementary material to allow for more detailed reporting of the trial methods and results than may be permissible within the typical length of some print journal articles. Full data and code sharing offers another, higher level of transparency and we recommend providing detailed information on whether this is happening or planned to happen (eg, after some time) in a randomised trial. CONSORTterm·dom urges clarity and transparency of reporting which reflects the actual trial design, conduct, and analysis. High quality reporting is an important step when considering issues related to reproducibility. 50 We encourage trial authors to detail what was done and to acknowledge if something was not done or was modified, ensuring alignment of information with that reported in the trial protocol, statistical analysis plan, and trial registry. A joint SPIRIT-CONSORT website ( https://www.consort-spirit.org/ ) has been established to provide more information about the CONSORTterm·dom and SPIRIT statements, including additional resources and training materials aimed at researchers, research trainees, journal editors, and peer reviewers. The website also includes resources aimed at patients and the public that explain the importance of clear and transparent reporting of randomised trials and their importance in the delivery of evidence based healthcare. CONSORTterm·dom 2025 represents a living guideline that will continue to be periodically updated to reflect new evidence and emerging perspectives. Such an approach is important to ensure the guidance remains relevant to end users, including authors, patients and the public, journal editors, and peer reviewers.