The difference in all-cause mortality between COVID-19 patients treated with standard of care plus placebo and those treated with standard of care alone: a network meta-analysis of randomised controlled trials of immunomodulatory kinase inhibitors

Objectives: The aim of this network meta-analysis (NMA) was to assess whether participants assigned to a placebo and standard of care (SoC) group had different major coronavirus disease 2019 (COVID-19)-related outcomes than those assigned to SoC alone. Design: Frequentist model-based NMA. Setting: We searched for randomised controlled trials (RCTs) of Janus kinase/Bruton tyrosine kinase inhibitors for the management of COVID-19. Participants: Patients with COVID-19 infection. Main outcome measures: The primary outcome was the 28-day all-cause mortality, and secondary outcomes were: (1) use of mechanical ventilation; (2) secondary bacterial infection; (3) acceptability (i.e. drop-out rate); and (4) safety (i.e. serious adverse events). We conducted an NMA using the frequentist model. Effect sizes were estimated using odds ratios (ORs) with 95% confidence intervals (95% CIs). Results: We identified 14 eligible RCTs enrolling a total of 13,568 participants with COVID-19. Participants assigned to placebo plus SoC had a significantly higher risk of 28-day all-cause mortality than those receiving SoC alone (OR = 1.39, 95% CI = 1.07-1.79). This finding did not change substantially by subgroup analysis stratified by epidemiology factor, pandemic history progression and statistical methodologic consideration. In addition, none of the treatments investigated were associated with a significantly different risk of secondary bacterial infection, acceptability or safety compared with the SoC group. Conclusions: This NMA suggested a higher all-cause mortality in patients treated with placebo plus SoC compared with those treated with SoC alone. However, caution is advised in interpreting these results due to the absence of a direct head-to-head comparison. Future research should critically evaluate the necessity of placebo administration in COVID-19 RCTs and consider alternative study designs to minimise potential biases. Trial registration: The current study was approved by the Institutional Review Board of the Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (TSGHIRB No. B-109-29) and registered in PROSPERO (CRD42022376217).