The CONSORT Statement: Application within and adaptations for orthodontic trials

High-quality randomized controlled trials (RCTs) are an integral part of evidence-based medicine. RCTs are the bricks and mortar of high-quality systematic reviews, which are important determinants of health care policy and clinical practice. For published research to be used most effectively, investigators and authors should follow the guidelines for accurate and transparent reporting of RCTs. The consolidated standards of reporting trials (CONSORT) statement and its extensions are among the most widely used reporting guidelines in biomedical research. CONSORT was adopted by the American Journal of Orthodontics and Dentofacial Orthopedics in 2004. Since 2011, this Journal has been actively implementing compliance with the CONSORT reporting guidelines. The objective of this explanatory article is to highlight the relevance and implications of the various CONSORT items to help authors to achieve CONSORT compliance in their research submissions of RCTs to this and other orthodontic journals.

Highlights

  • Randomized controlled trials (RCTs) are an integral part of evidence-based medicine.

  • Authors should follow the guidelines for accurate and transparent reporting of RCTs.

  • CONSORT guidelines are for RCT reporting.

  • This article highlights the relevance and implications of the CONSORT items.

Randomized controlled trials (RCTs) are an integral part of evidence-based medicine. Readers of reports of RCTs must be able to understand exactly how the trial was conducted to assess its relevance and methodologic rigor. Two key principles are that the trials could be replicated from the information provided and that the methods and findings should be described in enough detail to allow inclusion of the trial in a subsequent systematic review.

The consolidated standards of reporting trials (CONSORT) statement was developed to help improve the reporting of RCTs with guidance to researchers preparing reports of their clinical trials. The CONSORT checklist consists of 25 items covering all key aspects of clinical trials, setting standards on how to report the design, conduct, analysis, and interpretation of such studies. Several extensions to the main CONSORT guidelines cover more complicated designs such as cluster randomized and noninferiority trials; updated information is available at the CONSORT Web site ( www.consort-statement.org/extensions ). Over 600 biomedical journals, including the American Journal of Orthodontics and Dentofacial Orthopedics ( AJO-DO ) in 2004, have adopted the CONSORT guidelines, and many have also adopted additional CONSORT guidelines on abstract reporting. Despite the widespread acceptance of these recommendations, there remains considerable scope for improving the reporting of clinical trials.

The AJO-DO recognized that adoption does not guarantee compliance with the CONSORT guidelines and in 2011 implemented a scheme geared at improving compliance with CONSORT and so improve the reporting of RCTs in the Journal . This scheme includes videos, links to the CONSORT Web site, and active guidance for authors submitting reports of RCTs regarding compliance with the CONSORT guidelines. More recently, the reporting of RCTs by the AJO-DO has been reformatted with the introduction of subheadings to promote complete reporting and, by extension, to allow more efficient data extraction during the systematic review process.

Since these changes were introduced in the AJO-DO , published RCTs have shown dramatic improvements in reporting quality; this improvement reflects successful interactions among the editors, reviewers, and authors. All published trials submitted between 2011 and 2013 reported 33 of the 37 CONSORT items and subitems. CONSORT items referring to changes to methods (3b), changes to outcomes after the trial commenced (6b), interim analysis (7b), and trial stopping (14b) were not fully reported. However, there is still a need to improve the reporting in the initial submissions to limit the need for editorial input to improve CONSORT compliance. The objectives of this article are to explain the requirements of the AJO-DO for RCT submissions and to describe and communicate the importance of each item in the CONSORT checklist as it relates to orthodontics. This article is based on the CONSORT 2010 explanation and elaboration document for reporting parallel group randomized trials. A CONSORT-compliant published RCT has been uploaded on the AJO-DO Web site ( Annotated RCT Sample Article ) and will serve as the illustrative example.

Description of the checklist items and importance

The following explanations are based on the explanation and elaboration CONSORT document and are appropriately adapted to better target the AJO-DO ‘s audience ( Table I ).

Table I
CONSORT 2010 checklist of information to include when reporting a randomized trial
Section/topic Item (n) Checklist item
Title and abstract
1a Identification as a randomized trial in the title
1b Structured summary of trial design, methods, results, and conclusions (for specific guidance, see CONSORT for abstracts)
Introduction
Background and objectives 2a Scientific background and explanation of rationale
2b Specific objectives or hypotheses
Methods
Trial design 3a Description of trial design (such as parallel, factorial) including allocation ratio
3b Important changes to methods after trial commencement (such as eligibility criteria), with reasons
Participants 4a Eligibility criteria for participants
4b Settings and locations where the data were collected
Interventions 5 Interventions for each group with sufficient details to allow replication, including how and when they were actually administered
Outcomes 6a Completely defined prespecified primary and secondary outcome measures, including how and when they were assessed
6b Any changes to trial outcomes after the trial commenced, with reasons
Sample size 7a How sample size was determined
7b When applicable, explanation of any interim analyses and stopping guidelines
Randomization
Sequence generation 8a Method used to generate the random allocation sequence
8b Type of randomization; details of any restriction (such as blocking and block size)
Allocation concealment 9 Mechanism used to implement the random allocation sequence (eg, sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned
Implementation 10 Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions
Blinding 11a If done, who was blinded after assignment to interventions (eg, participants, care providers, those assessing outcomes) and how
11b If relevant, description of the similarity of interventions
Statistical methods 12a Statistical methods used to compare groups for primary and secondary outcomes
12b Methods for additional analyses, such as subgroup analyses and adjusted analyses
Results
Participant flow (diagram is strongly recommended) 13a For each group, numbers of participants who were randomly assigned, received intended treatment, and were analyzed for the primary outcome
13b For each group, losses and exclusions after randomization, with reasons
Recruitment 14a Dates defining the periods of recruitment and follow-up
14b Why the trial ended or was stopped
Baseline data 15 A table showing baseline demographic and clinical characteristics for each group
Numbers analyzed 16 For each group, number of participants (denominator) included in each analysis, and whether the analysis was by original assigned groups
Outcomes and estimation 17a For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% CI)
17b For binary outcomes, presentation of both absolute and relative effect sizes is recommended
Ancillary analyses 18 Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing prespecified from exploratory
Harms 19 All important harms or unintended effects in each group (for specific guidance, see CONSORT for harms)
Discussion
Limitations 20 Trial limitations, addressing sources of potential bias, imprecision, and, if relevant, multiplicity of analyses
Generalizability 21 Generalizability (external validity, applicability) of the trial findings
Interpretation 22 Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence
Other information
Registration 23 Registration number and name of trial registry
Protocol 24 Where the full trial protocol can be accessed, if available
Funding 25 Sources of funding and other support (eg, supply of drugs) and the role of funders

Title and abstract

CONSORT item 1a is “identification as a randomized trial in the title.”

Example: “Survival of bonded lingual retainers (outcome) in orthodontic patients (participants) with chemical (intervention) or photo polymerization (comparison) over a 2-year period: A single-center, randomized controlled clinical trial.”

Explanation: To help ensure that a study is appropriately indexed and easily identified, authors should use the word “randomized” in the title to indicate that the participants were randomly assigned to their comparison groups. Authors are also encouraged (not a CONSORT item) to structure the title in the PICO+ format, providing information about participants, interventions, comparisons, and outcomes. The + sign indicates the possible inclusion of additional information pertaining to blinding, number of centers, time, and so on.

CONSORT item 1b is “structured summary of trial design, methods, results, and conclusions” (for specific guidance, see CONSORT for abstracts).

Explanation: There is specific guidance for reporting abstracts of RCTs ( Table II ). Well-written and detailed abstracts clearly describing the trial facilitate the initial assessment of an article and aid the retrieval of trials from databases for inclusion in systematic reviews. The abstract is the only component of an article that is read by many clinicians; hence, the accuracy and the quality of its information are critical. Reporting of the abstract items will be considered at the end of this article, since almost all information relevant to the abstract will be discussed in detail in under the main CONSORT guideline items.

Table II
CONSORT for abstracts checklist of items to include when reporting a randomized trial
Item Description
Title Identification of the study as randomized
Authors Contact details for the corresponding author
Trial design Description of the trial design (eg, parallel, cluster, noninferiority)
Methods
Participants Eligibility criteria for participants and the settings where the data were collected
Interventions Interventions intended for each group
Objective Specific objective or hypothesis
Outcome Clearly defined primary outcome for this report
Randomization How participants were allocated to interventions
Blinding (masking) Whether participants, care givers, and those assessing the outcomes were blinded to group assignments
Results
Numbers randomized Number of participants randomized to each group
Recruitment Trial status
Numbers analyzed Number of participants analyzed in each group
Outcome For the primary outcome, a result for each group and the estimated effect size and its precision
Harms Important adverse events or side effects
Conclusions General interpretation of the results
Trial registration Registration number and name of trial register
Funding Source of funding

This item is specific to conference abstracts.

Title and abstract

CONSORT item 1a is “identification as a randomized trial in the title.”

Example: “Survival of bonded lingual retainers (outcome) in orthodontic patients (participants) with chemical (intervention) or photo polymerization (comparison) over a 2-year period: A single-center, randomized controlled clinical trial.”

Explanation: To help ensure that a study is appropriately indexed and easily identified, authors should use the word “randomized” in the title to indicate that the participants were randomly assigned to their comparison groups. Authors are also encouraged (not a CONSORT item) to structure the title in the PICO+ format, providing information about participants, interventions, comparisons, and outcomes. The + sign indicates the possible inclusion of additional information pertaining to blinding, number of centers, time, and so on.

CONSORT item 1b is “structured summary of trial design, methods, results, and conclusions” (for specific guidance, see CONSORT for abstracts).

Explanation: There is specific guidance for reporting abstracts of RCTs ( Table II ). Well-written and detailed abstracts clearly describing the trial facilitate the initial assessment of an article and aid the retrieval of trials from databases for inclusion in systematic reviews. The abstract is the only component of an article that is read by many clinicians; hence, the accuracy and the quality of its information are critical. Reporting of the abstract items will be considered at the end of this article, since almost all information relevant to the abstract will be discussed in detail in under the main CONSORT guideline items.

Table II
CONSORT for abstracts checklist of items to include when reporting a randomized trial
Item Description
Title Identification of the study as randomized
Authors Contact details for the corresponding author
Trial design Description of the trial design (eg, parallel, cluster, noninferiority)
Methods
Participants Eligibility criteria for participants and the settings where the data were collected
Interventions Interventions intended for each group
Objective Specific objective or hypothesis
Outcome Clearly defined primary outcome for this report
Randomization How participants were allocated to interventions
Blinding (masking) Whether participants, care givers, and those assessing the outcomes were blinded to group assignments
Results
Numbers randomized Number of participants randomized to each group
Recruitment Trial status
Numbers analyzed Number of participants analyzed in each group
Outcome For the primary outcome, a result for each group and the estimated effect size and its precision
Harms Important adverse events or side effects
Conclusions General interpretation of the results
Trial registration Registration number and name of trial register
Funding Source of funding

This item is specific to conference abstracts.

Introduction

The introduction includes the background and the objectives.

Background and objectives

CONSORT item 2a is “scientific background and explanation of rationale.”

Example: “A significant problem continues to relate to bond failures, estimated at 6% to 25%, depending on the placement technique and the observation period… Although light-cured materials offer longer working times and improved moisture control, no randomized controlled trial has been published investigating the importance of these theoretical advantages.”

Explanation: It is good practice at the planning stage of the trial to first search the literature to identify the available evidence on the topic of interest. This evidence can be limited or abundant, and identification of a high-quality systematic review, if available, is desirable. A recent high-quality systematic review, which summarizes the existing evidence, can serve as a reference in terms of what is known and what remains unclear regarding the efficacy and safety of the intervention of interest. The Declaration of Helsinki considers research on human subjects without thorough knowledge of the existing literature as unethical. It is also unethical to plan a trial to answer a question that has already been answered. A trial is justified when there is genuine uncertainty (equipoise), based on the existing evidence, regarding the effectiveness of the intervention at hand.

In the RCT example, a systematic review is not cited, but the authors explicitly stated that no RCT has been published investigating the theoretical advantages of light curing vs chemical curing.

CONSORT item 2b is “specific objectives or hypotheses.”

Example: “In this study, we aimed to compare the survival of mandibular lingual retainers placed by using either chemical or photopolymerization after orthodontic treatment.”

Explanation: The objectives are the questions that the trial was designed to answer. They often relate to the efficacy of a particular therapeutic or preventive intervention. Hypotheses are prespecified questions being tested to help meet the objectives. Hypotheses are more specific than objectives and are amenable to explicit statistical evaluations. In practice, objectives and hypotheses are not always easily differentiated.

Methods

Trial design

CONSORT item 3a is “description of the trial design (eg, parallel, factorial) including the allocation ratio.”

Example: “This was a parallel-group, randomized, active controlled trial with a 1:1 allocation ratio.”

Explanation: The most common type of trial design is the parallel design; however, other designs such as cross-over, cluster randomized, noninferiority, factorial, and hybrids of those exist and should be specified. A study design commonly used in dentistry is the split-mouth design, as well as studies including elements of clustered designs. Such designs occur when several observations are collected from each patient from multiple sites and tissues such as the number of teeth or periodontal sites or structures. Different trial designs have characteristics that may influence the conduct and analysis of the trial; these details should, therefore, be described clearly. It is important that specific details (design and allocation ratio) are given as shown under this subheading.

CONSORT item 3b is “important changes to methods after trial commencement (such as eligibility criteria), with reasons.”

Example: “No changes to the methods after trial commencement occurred.”

Explanation: Changes between the study protocol and how the trial was actually done are common and should be documented appropriately. Possible reasons for changes—eg, to eligibility criteria or duration of follow up—include new external evidence, inability to recruit a sufficient number of patients, and financial constraints. For some “adaptive” trials, the protocol allows for limited changes following prespecified rules, when the sample size and duration of the trial are not determined before commencement. The protocol should indicate the adjustments planned under the different change scenarios, and the changes should be documented, explained, and justified in the published article. Any modifications to the trial design should be fully reported to help the reader interpret the results, whether they were anticipated in the protocol or in response to changing circumstances.

The RCT at hand reported no changes after the commencement of the trial; however, no published protocol allowed this to be verified, and this is reported at the end of the abstract.

Participants

CONSORT item 4a is “eligibility criteria for participants.”

Example: “The following selection criteria were applied: no active caries, restorations, or fractures on the mandibular anterior teeth; no periodontal disease; and adequate oral hygiene.”

Explanation: Eligibility criteria and information on participants and settings should be outlined clearly because they have implications for the relevance of the trial results to other settings (generalizability). Because eligibility criteria are applied before randomization, they do not affect the internal validity (methodologic quality) of a trial. The common distinction between inclusion and exclusion criteria is unnecessary; the same criterion can be phrased to include or exclude participants.

CONSORT item 4b is “settings and locations where the data were collected.”

Example: “Consecutive patients who had completed orthodontic treatment with fixed appliances were recruited at the private practice of the first author (N.P.) from April 2009 to November 2010.”

Explanation: A clear description of the setting and locations where the data were collected is important to allow the reader to decide whether the findings are relevant to her or his own setting. Information on the geographic location, the number of participating centers, the available facilities, the involved care providers, and their levels of expertise should also be clearly described. Trial results may differ substantially, for example, between centers with state-of-the-art facilities with highly trained personnel and studies undertaken by relative novices in poorly equipped clinics.

Interventions

CONSORT item 5 is “interventions for each group with sufficient details to allow replication, including how and when they were actually administered.”

Example: “All patients received a soft bonded lingual retainer of 0.022-in (Tru-Chrome multi-stranded wire; Rocky Mountain Orthodontics, Denver, Colo) that was fabricated intraorally… In the chemical polymerization group, Maximum Cure 2-part liquid adhesive (Reliance Orthodontic Products, Itasca, Ill) was mixed and applied on the wire and the teeth, and Excel 2-part paste (Reliance Orthodontic Products) was mixed, loaded on a syringe dispenser, and applied. The dental floss was removed after 7 minutes. In the photopolymerization group, a light-cured liquid (Assure; Reliance Orthodontic Products) and a paste in 2 layers (Flow-Tain; Reliance Orthodontic Products) were placed on the wire and the adjacent enamel, and light-cured for 9 seconds per tooth with a plasma light (Ortholite; 3M Unitek, Monrovia, Calif).”

Explanation: A clear description of each intervention in sufficient detail to allow a knowledgeable researcher to duplicate the experiment should be provided. For example, in a multicenter trial, as a minimum, the exact method of standardization of the administration, the duration, and the timing of the treatment should be outlined. A pharmacologic intervention would require explanation of the drug administered in conjunction with the mode of delivery, dosage, and frequency, and whether the control or placebo was indistinguishable from the “active pill” in terms of shape, color, smell, and taste. For other types of interventions, the CONSORT extension for nonpharmacologic trials describes the reporting requirements. Some important issues are the standardization of the delivery of the interventions, description of the various components of the interventions, and how adherence of the care providers to the protocol was assessed. A clear description further facilitates the implementation of valid comparisons and informed decisions regarding the inclusion of the primary study in systematic reviews.

Outcomes

CONSORT item 6a is “completely defined prespecified primary and secondary outcome measures, including how and when they were assessed.”

Example: “The main outcome was any first-time failure of the lingual retainer. The secondary outcome was the pattern of failure based on the adhesive remnant… The patients were advised to visit the orthodontist initially at 1, 3, and 6 months after retainer placement, followed by scheduled appointments at 12, 18, and 24 months… When scheduled appointments were unfeasible, particularly approaching the end of the trial, an assessment of retainer integrity was made over the telephone.”

Explanation: It is common for trials to have several outcomes, often identified as primary and secondary. All outcomes should be clearly defined and prespecified with an explicit description of how and when they were assessed. The definition of each outcome should be clear enough to allow other investigators to use the same outcome in a trial or to be confident of the similarities and differences of the outcome in the context of a systematic review. Declaration of prespecified outcomes, especially the primary outcome, is important, since, like registration and protocol prepublication, it mitigates against the problem of selective reporting of “interesting” outcomes. This is more likely when multiple outcomes or multiple time points of data collection are planned. Additionally, recording of several outcomes, and consequently multiple testing, invokes the problems associated with multiplicity and misleading interpretations.

When assessing the evidence for or against the effectiveness of an intervention, the balance of benefits and harms is an important consideration. A clear description of harms that were recorded should be provided. In nonpharmacologic trials, it is particularly important to specify the skills and the number of persons assessing the outcomes.

CONSORT item 6b is “any changes to trial outcomes after the trial commenced, with reasons.”

Example: “There were no outcome changes after trial commencement.”

Explanation: Reviews of publications show that discrepancies between planned and presented outcomes are common. Outcomes initially planned to be the primary outcomes in the original trial protocol may be portrayed as secondary outcomes, whereas new primary outcomes can be introduced in the published article. Selective outcome reporting and presentation of “interesting” findings has also been documented. Therefore, clear descriptions of any outcome changes with the reasons for the alterations will enhance transparency. No outcome changes are reported in the RCT described; however, there is no prepublished protocol to confirm this.

Sample size

CONSORT item 7a is “how sample size was determined.”

Example: “Calculation of sample size was based on the ability to detect a clinically relevant difference in the risk of first-time failure (primary outcome) of 20% between the 2 trial arms (15% vs 35% with α = 0.05 and power of 85%). Foek et al found a 35% failure rate for light-cured lingual retainers; we used this value as our reference for the sample calculation. This calculation indicated that 93 participants were required in each arm; this was rounded up to 110 to account for losses to follow-up.”

Explanation: RCTs should have enough power to detect a clinically important difference between the treatment groups if such a difference exists, or to confirm the lack of a difference. It is an obligation of the investigators to conduct appropriate sample-size calculations driven by clinical importance and reasonable assumptions.

Authors should provide enough information so that a knowledgeable reader can reproduce the sample-size calculation. The sample-size calculation is usually based on the primary outcome, which should be clearly identified. For continuous outcomes, the authors should report the expected result in the control group, the expected difference of the intervention group from the control, the standard deviations, and the alpha and power levels. For binary outcomes, the same information is required, except for the standard deviation. In designs where clustering effects are expected, the value of the intracluster correlation coefficient should be provided. For split-mouth designs, common in orthodontics, the assumed correlations between sites should be specified. Finally, any provisions for expected losses to follow-up should also be described. Authors should ideally explain the rationale for the values used in the calculation.

A post hoc analysis to justify the sample size is considered inappropriate: power can be judged by inspecting the effect size and confidence intervals and the uncertainty that they convey.

CONSORT item 7b is “when applicable, explanation of any interim analyses and stopping guidelines.”

Example: “Not applicable.”

Explanation: Participants can be recruited and treated over a prolonged period. If an obvious difference between interventions emerges early in the trial, the study may be stopped prematurely for ethical reasons. This eventuality can be addressed by inspection of the interim results, ideally by an independent data-monitoring committee. However, performing multiple statistical examinations without appropriate corrections can lead to erroneous results and interpretations. Authors should report whether they or a data-monitoring committee took several “looks” at the data; if so, how many were there, what triggered them, what statistical methods were used (including any formal stopping rule), and whether they were planned before the start of the trial, before the data-monitoring committee saw any interim data by allocation, or some time thereafter.

No interim analyses or stopping guidelines were reported in the example study.

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Apr 6, 2017 | Posted by in Orthodontics | Comments Off on The CONSORT Statement: Application within and adaptations for orthodontic trials
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