What to write
Scientific background and rationale
Example
“Most problems with shoulder pain are managed in primary care by physiotherapists and GPs [general practitioners] . . . Evidence from small, short-term trials suggests that physiotherapist-prescribed exercise is promising. However, a Cochrane review highlighted the insufficient evidence about the treatment's long-term clinical effectiveness and cost-effectiveness. Despite widespread provision, uncertainty exists about which types of exercise and levels of physiotherapy supervision are associated with the best outcomes. This evidence is limited by problems in study design and lack of comparator groups. Progressive resistance training to improve muscular strength, whether supervised or home based, has been identified as a core component of exercise for patients with rotator cuff disorders. Subacromial corticosteroid injections are commonly used to reduce local tissue inflammation and pain. Compared with placebo, corticosteroid injections have short-term benefit in the shoulder, although the longer-term benefits and harms are not known. Corticosteroid injections are being used increasingly in clinical practice alongside physiotherapy for the management of people with rotator cuff disorders; hence justification for investigating corticosteroid injection in the GRASP (Getting it Right: Addressing Shoulder Pain) trial alongside physiotherapist-prescribed exercise.”1
Explanation
Typically, the introduction of the trial report consists of free-flowing text, in which authors explain the scientific background and rationale for their trial, and its general outline. The rationale may be explanatory (eg, to assess the possible influence of a drug on renal function under tightly regulated conditions) or pragmatic (eg, to guide practice by comparing the benefits and harms of two treatments in a clinical setting). Authors should report any evidence of the benefits and harms of active interventions included in a trial and should suggest a plausible explanation for how the interventions might work, if this is not obvious. Understanding the rationale or theory underpinning an intervention helps readers to understand which aspects or components are likely to be essential to its efficacy.2 In addition, authors should justify the choice of comparator(s).3,4 The choice of the comparator (active or placebo) will influence effect estimates. It could raise ethical concerns if patients could be allocated to a placebo or to a suboptimal treatment while an active treatment has been proven effective. Authors should justify the need for the trial they conducted and show that there was equipoise about the best treatment for the condition in the population being studied.
The Declaration of Helsinki states that biomedical research involving people should be based on a thorough knowledge of the scientific literature.5 It is unethical to expose humans unnecessarily to the risks of research. Some clinical trials have been shown to have been unnecessary because the question they addressed had been, or could have been, answered by a systematic review of the existing literature.6–8 Thus, the need for a new trial should be justified in the introduction. Ideally, this justification should include a reference to one or more systematic reviews of previous trials. In the absence of a published systematic review, authors should report and summarise the results of previous relevant trials or note their absence.9 The percentage of published trial reports that cite a systematic review of pre-existing evidence where one is available has increased over time, but over a quarter still fail to do so.10
Training
The UK EQUATOR Centre runs training on how to write using reporting guidelines.
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