Objectives: To describe the prevalence of risks of bias in randomised trials of therapeutic interventions for COVID-19. Study design and setting Systematic review and risk of bias assessment performed by two independent reviewers of a random sample of 40 randomised trials of therapeutic interventions for moderate-severe COVID-19. We used the RoB 2.0 tool to assess risk of bias which evaluates bias under five domains as well as an overall assessment of each trial as high or low risk of bias. Results: Of the 40 included trials, 19 (47%) were at high risk of bias, and this was particularly frequent in trials from low-middle income countries (11/14, 79%). Potential deviations to intended interventions (i.e. control participants accessing experimental treatments) were considered a potential source of bias in some studies (14, 35%); as to was the risk due to selective reporting of results (6, 15%). The randomisation process was considered at low risk of bias in most studies (34, 95%); as to was missing data (36, 90%); and measurement of the outcome (35, 87%). Conclusion: Many randomised trials evaluating COVID-19 interventions are at risk of bias, particularly those conducted in low-middle income countries. Biases are mostly due to deviations from intended interventions and partly due to the selection of reported results. Use of placebo control and publicly available protocol can mitigate many of these risks.
Fuente: International Journal of Infectious Diseases
Available online 18 May 2022