Background and importance A greater benefit was suggested with early treatment with remdesivir against COVID-19.

Aim and objectives To develop a systematic review and methodological interpretation of subgroup analyses according to timing of use of remdesivir in COVID-19.

Material and methods A bibliographic review in MEDLINE was conducted up to 10 October 2020. The ‘Clinical Queries/Narrow’ tool was used with the search strategy: ((Therapy/Narrow[filter]) AND (remdesivir AND COVID)). Randomised clinical trials (RCTs) with subset analysis about early and late use of remdesivir (≤10 vs >10 days from symptom onset, or ≤9 vs >9 days) were selected. The rest of the studies were excluded. All endpoints with subgroup analysis regarding timing of remdesivir use were assessed. Two methodologies were applied. The first considered statistical interaction among subsets, prespecification, biological plausibility and consistency of the subgroup analyses of similar RCTs.¹ The second methodology was a validated tool with preliminary questions to discard subset analysis without minimal relevance, and a checklist.² This checklist assigned a score related to a recommendation for applicability of subgroup analysis in clinical practice.

Results 20 results were found after review; 16 studies were excluded because they were not RCTs and 1 study had no efficacy evaluation of remdesivir. Therefore, three RCTs were selected. Endpoints considered were: time to clinical improvement, mortality, viral load, and clinical status at days 11 and 15. According to the first methodology, no statistical interaction was observed in the outcomes of the RCTs. Prespecification was established in time to clinical improvement, and clinical status at day 15 of an RCT. Biological plausibility was described in the subset analysis of each endpoint of the RCTs. No consistency of subgroup analyses were found. The second methodology discarded the applicability of the subset analysis through preliminary questions in two RCTs because of the absence of minimal relevance. For the third RCT, ‘null’ recommendation (score −3 points) of clinical applicability was reached for clinical status at day 11.

Conclusion and relevance No differences were found between early and late use of remdesivir in COVID-19. We developed the first study with a systematic review and methodology about subgroup analysis of timing of use of remdesivir.

References and/or acknowledgements

1. Sun X, et al. How to use a subgroup analysis: users’ guide to the medical literature. JAMA 2014;311:405–11.

2. Gil-Sierra MD, et al. Checklist for clinical applicability of subgroup analysis. J Clin Pharm Ther 2020;45:530–8.

Conflict of interest No conflict of interest