Open Science
Introduction
Methods
Results
Discussion
Intervention and comparator delivery
Item 24b: Concomitant care received during the trial for each group
Example
“The principal investigators invited hospitals with the capability to provide the current standard of care for covid-19 to participate in the study. Minimum requirements for the standard of care included the provision of intravenous fluids, supplemental oxygen, regular laboratory testing, SARS-CoV-2 testing, haemodynamic monitoring, and intensive care, as well as the ability to deliver concomitant medications . . .
“90 (60%) patients received concomitant drug treatment before randomisation. Among these, 52 (35%) patients received antiviral treatment [table 9] . . . Concomitant treatments, including antiviral agents, antibiotics, and systemic glucocorticoid therapy, were similar in the two groups [table 9] [447]"
Explanation
Concomitant care refers to any additional treatments, interventions, or medications that participants may have received during the trial period, in addition to the study interventions. Relevant concomitant care refers to interventions that could have affected the outcome. Transparently reporting this information is essential for readers to understand the context in which the trial was conducted and be able to assess the potential influence of concomitant care on the trial’s results. Particularly, readers should be aware of any unequal use of concomitant care that might affect the outcome between the intervention and comparator groups [448]. This is particularly important when the trials are not fully blinded [449]. This information could be particularly important for evaluating the risk of bias due to deviations from the intended interventions, an important domain of the risk-of-bias tool developed by Cochrane [210, 211].
Nevertheless, this information is poorly reported. A review of 164 cardiovascular clinical trials published in five influential medical journals from 2011 to 2021 showed that cointerventions were inadequately reported in 71% of the trials [450] and that trials with deficient reporting had larger treatment effect estimates on average [451]. In rheumatology, an assessment of 109 trials in leading journals from 2018 to 2020 found that only 57% of randomised trials provided the number of patients on concomitant medications at baseline, and only 5% reported the cumulative or mean exposure data for concomitant medications [452].
Authors should report the number and percentage of participants receiving the different relevant concomitant care in each arm and, where relevant, the cumulative or average for each concomitant intervention taken over the trial period for each group.