What to write
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
Examples
“Each sulfadoxine–pyrimethamine course consisted of three tablets containing 500 mg of sulfadoxine and 25 mg of pyrimethamine (unbranded generic sulfadoxine–pyrimethamine, Medopharm, Chennai, India; quality controlled by Durbin, Hayes, UK) given as a single oral dose for 1 day (appendix p 2). Each dihydroartemisinin–piperaquine course was dosed according to the bodyweight of each participant and consisted of three to five tablets containing 40 mg of dihydroartemisinin and 320 mg of piperaquine (Alfasigma, Bologna, Italy), given orally once a day for 3 consecutive days. Each dose of azithromycin consisted of two tablets containing 500 mg (Universal Corporation, Nairobi, Kenya) given orally once daily for 2 consecutive days (cumulative dose of 2 g) at the same time as the first and second daily dose of dihydroartemisinin–piperaquine at enrolment. The placebo tablets were also provided by Universal Corporation and had the same appearance as active azithromycin (appendix p 2). The first daily dose was administered in the study clinic under the direct supervision of the study staff, combined with a slice of dry bread or a biscuit. The daily doses on the second and third days were self-administered at home at approximately the same time of the day and in a similar manner as the first dose taken under observation in the clinic.”1
“The experimental group received 6 sessions of standard OMT (osteopathic manipulative treatment), and the control group 6 sessions of sham OMT, each session at 2-week intervals. For both experimental and control groups, each session lasted 45 minutes and consisted of 3 periods: (1) interview focusing on pain location, (2) full osteopathic examination, and (3) intervention consisting of standard or sham OMT. Briefly, in both groups, practitioners assessed 7 anatomical regions for dysfunction (lumbar spine, root of mesentery, diaphragm, and atlantooccipital, sacroiliac, temporomandibular, and talocrural joints) and applied sham OMT to all areas or standard OMT to those that were considered dysfunctional. All health care providers were board-certified nonphysician, nonphysiotherapist osteopathic practitioners (Répertoire National de la Certification Professionnelle, niveau 1). They all received a 2-day training according to international standards to deliver both standard and sham OMT. Full descriptions of osteopathic practitioner training and interventions are provided in eAppendices 3 and 4 in Supplement 2. In both groups, pharmacological interventions, nonpharmacological interventions, and spinal surgery were allowed. Cointerventions were self-reported at 3, 6, and 12 months by use of a standardized checklist (eAppendix 5 in Supplement 2).”2
Explanation
Complete reporting of the intervention and comparator details is essential to enable readers to understand the study results and adequately translate them to clinical practice. Several studies have shown poor reporting of interventions and comparators in randomised trials.3–89–12 Authors should describe each intervention thoroughly, including control interventions, or use of placebo procedure.13,14 The description should provide sufficient detail to allow replication, such as to allow a clinician wanting to use the intervention to know exactly how to administer the intervention/comparator that was evaluated in the trial.4 Key information includes the different components of the intervention/comparator, how and when it should be administered, the intervention/comparator material (ie, any physical or informational materials used in the intervention/comparator, including those provided to participants or used in intervention/comparator delivery or in training of providers and where it can be accessed (eg, online appendix, URL)); the procedure for tailoring the intervention/comparator to individual participants, and how fidelity15 (ie, the extent to which the intervention/comparator were implemented as planned in the protocol by care providers) or adherence15 (ie, the extent to which trial participants implement the intervention/comparator as planned in the protocol) were assessed or enhanced (see below for more examples).
Drug17
Generic name
Manufacturer
Dose
Route of administration (eg, oral, intravenous)
Timing
Titration regimen if applicable
Duration of administration
Procedure for tailoring the intervention to individual participants
Conditions under which interventions are withheld
Whether and how adherence of patients to the intervention was assessed or enhanced
Any physical or informational materials used in the intervention and where the materials can be accessed.
Rehabilitation, behavioural treatment, education, and psychotherapy, etc16,17
Qualitative information
Theory/rationale for essential intervention elements
Content of each session
Mode of delivery (individual/group, face to face/remote)
Whether the treatment is supervised
The content of the information exchanged with participants
The materials used to give information
Procedure for tailoring the intervention to individual participants
Whether and how the interventions were standardised
Background and expertise of individuals delivering the interventions
Whether the same care providers delivered interventions across trial groups
Whether and how adherence of individuals delivering the interventions to the protocol was assessed or enhanced
Whether and how adherence of patients to the intervention protocol was assessed and/or enhanced
Any physical or informational materials used in the intervention and where the materials can be accessed.
Quantitative information
Intensity of the intervention where appropriate
Number of sessions
Session schedule
Session duration
Duration of each main component of each session
Overall duration of the intervention.
Surgery, technical procedure, or implantable device16
Preoperative care relevant details
Intraoperative care relevant details
Configuration of any device
Postoperative care relevant details
Procedure for tailoring the intervention to individual participants
Whether and how the interventions were standardised
Background and expertise of individuals delivering the interventions
Whether the same care providers delivered interventions across trial groups
Whether and how adherence of individuals delivering the interventions to the protocol was assessed or enhanced
Any physical or informational materials used in the intervention and where the materials can be accessed.
Assessing fidelity and adherence can be complex and vary according to the intervention/comparator (eg, one-off, short term repeated, long term repeated). Various deviations to the protocol can occur. For example, participants might initiate the intervention but then discontinue the intervention completely and permanently after a specific period of time, discontinue the intervention temporarily, reduce the dose, or modify the schedule. If relevant, authors should provide the prespecified definition for classifying participants as being treated as planned or not.
In addition, authors should indicate whether criteria were used to guide intervention/comparator modifications and discontinuations and where applicable describe these criteria. This information could be particularly important to evaluate the risk of bias due to deviations from the intended interventions,18,19 an important domain of the risk-of-bias tool developed by Cochrane.18 Assessing this domain requires a clear understanding of, and ability to distinguish between, deviations that occur as planned in the protocol and deviations that arise due to the experimental context.
The research question (ie, explanatory v pragmatic) will affect the standardisation of the intervention/comparator as well as how adherence or fidelity is assessed or enhanced. In explanatory trials, the aim is to estimate treatment effect under ideal circumstances. The intervention/comparator are usually highly standardised with close monitoring of fidelity and adherence to the intervention/comparator and strategies to increase them. In contrast, pragmatic trials aim to determine treatment effect in clinical conditions. The intervention and comparator are usually highly flexible, and measurement of fidelity and adherence are unobstructive with no strategies to maintain or improve them. Nevertheless, assessing fidelity and adherence to the intervention/comparator, or at least recording the most important components of the intervention/comparator, is necessary to understand what was actually administered to participants. This is particularly important for complex interventions where diversity in the implementation of the intervention is expected. For example, in a pragmatic trial assessing a surgical procedure where the procedure is left to surgeons’ choice, investigators should plan to systematically record key elements related to pre-operative care, anaesthesia, the surgical approach, and post-operative care. This information is essential to provide a relevant description of the intervention that was actually provided when the trial is completed.
If the control group or intervention group received a combination of interventions, the authors should provide a thorough description of each intervention, an explanation of the order in which the combination of interventions were planned to be introduced or withdrawn, and the triggers for their introduction if applicable. Some complex interventions will require the development of specific documentation (eg, training materials, intervention manuals). Authors should make these available and indicate where they can be accessed.
If the control group is to receive usual care, it is important to describe what that constitutes so that readers can assess whether the comparator differs substantially from usual care in their own setting.20 Various approaches could be used: standardising usual care to be in line with specific guidelines; or asking practitioners to treat control patients according to their own preference, which could result in heterogeneity of the care provided particularly between centres and over time.21 Usual care can vary substantially across sites and patients, as well as over the duration of the trial. Further, it is important to clarify if the experimental group also received usual care in addition to the experimental intervention, and what actually differed between the groups. Usual care is frequently incompletely reported. In a review of 214 paediatric trials, the descriptions of standard of care were more often incomplete than the description of the intervention arms within the same study as measured by the TIDieR checklist (mean 5.81 (standard deviation (SD) 2.13) v 8.45 (SD 1.39)).11
If the control group is to receive a placebo, specific considerations need to be accounted for. Some evidence showed that placebos are insufficiently described.22 Placebo could have several different aspects from pills to saline injections or more complex interventions such as sham interventions (eg, sham surgery) or attention control interventions. Authors should report the same level of details as required for the intervention—that is, content of the placebo or different component of the placebo, how and when it should be administered, material, procedure for tailoring the placebo to individual participants, and how fidelity and adherence were assessed or enhanced.13 Complete reporting of the placebo is needed to understand what intervention effect is measured in the trial.23 A network meta-analysis of osteoarthritis trials showed that different placebo interventions (oral, intra-articular, topical, oral and topical) had different effects and can impact the relative effect estimate of active treatments.24
Further, the trial groups could receive different concomitant care in addition to the assigned trial interventions. Concomitant care could impact trial outcomes and bias effect estimates. To facilitate interpretation of study results and risk-of-bias assessments, authors should report relevant concomitant care that was allowed or prohibited where relevant.
Specific guidance has been developed to improve the reporting of interventions, particularly TIDieR,17 TIDieR-Placebo for placebo and sham controls,13 and the CONSORT extensions for non-pharmacological treatments.16 Authors could consult these for more detailed information.
Training
The UK EQUATOR Centre runs training on how to write using reporting guidelines.
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