Standard of care for COVID-19 in randomized clinical trials registered in trial registries and published in preprint servers and scholarly journals: a cross-sectional study

BACKGROUND: The concept of standard of care (SoC) treatment is commonly utilized in clinical trials. However, in a setting of an emergent disease, such as COVID-19, where there is no established effective treatment, it is unclear what the investigators considered as the SoC in early clinical trials. The aim of this study was to analyze and classify SoC reported in randomized controlled trial (RCT) registrations and RCTs published in scholarly journals and on preprint servers about treatment interventions for COVID-19. METHODS: We conducted a cross-sectional study. We included RCTs registered in a trial registry, and/or published in a scholarly journal, and/or published on preprint servers medRxiv and bioRxiv (any phase; any recruitment status; any language) that aim to compare treatment interventions related to COVID-19 and SoC, available from January 1, 2020, to October 8, 2020. Studies using „standard“ treatment were eligible for inclusion if they reported they used standard, usual, conventional, or routine treatment. When we found such multiple reports of an RCT, we treated those multiple sources as one unit of analysis. RESULTS: Among 737 unique trials included in the analysis, 152 (21%) reported that SoC was proposed by the institutional or national authority. There were 129 (18%) trials that reported component(s) of SoC; the remaining trials simply reported that they used SoC, with no further detail. Among those 129 trials, the number of components of SoC ranged from 1 to 10. The most commonly used groups of interventions in the SoC were antiparasitics (62% of the trials), antivirals (57%), antibiotics (31%), oxygen (17%), antithrombotics/anticoagulants (14%), vitamins (13%), immunomodulatory agents (13%), corticosteroids (12%), analgesics/antipyretics (12%). Various combinations of those interventions were used in the SoC, with up to 7 different types of interventions combined. Posology, timing, and method of administration were frequently not reported for SoC components. CONCLUSION: Most RCTs (82%) about treatment for COVID-19 that were registered or published in the first 9 months of the pandemic did not describe the “standard of care” they used. Many of those interventions have, by now, been shown as ineffective or even detrimental. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12874-022-01646-1.