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IL-6 inhibition in the treatment of COVID-19: a meta-analysis and meta-regression

Research output: Contribution to journalArticlepeer-review

Emmanuel Tharmarajah, April Buazon, Vishit Patel, Jennifer R Hannah, Maryam Adas, Victoria B Allen, Katie Bechman, Benjamin D Clarke, Deepak Nagra, Sam Norton, Mark D Russell, Andrew I Rutherford, Mark Yates, James B Galloway

Original languageEnglish
Pages (from-to)178-185
Number of pages8
JournalJournal of Infection
Issue number5
Early online date18 Mar 2021
E-pub ahead of print18 Mar 2021
PublishedMay 2021

Bibliographical note

Funding Information: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. MDR and VBA receive funding from the National Institute for Health Research. BDC receives funding from Innovate UK. ET, AB, VP, JRH contributed equally to this work. Publisher Copyright: © 2021 The British Infection Association Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors


Objectives: Multiple RCTs of interleukin-6 (IL-6) inhibitors in COVID-19 have been published, with conflicting conclusions. We performed a meta-analysis to assess the impact of IL-6 inhibition on mortality from COVID-19, utilising meta-regression to explore differences in study results. Methods: Systematic database searches were performed to identify RCTs comparing IL-6 inhibitors (tocilizumab and sarilumab) to placebo or standard of care in adults with COVID-19. Meta-analysis was used to estimate the relative risk of mortality at 28 days between arms, expressed as a risk ratio. Within-study mortality rates were compared, and meta-regression was used to investigate treatment effect modification. Results: Data from nine RCTs were included. The combined mortality rate across studies was 19% (95% CI: 18, 20%), ranging from 2% to 31%. The overall risk ratio for 28-day mortality was 0.90 (95% CI: 0.81, 0.99), in favour of benefit for IL-6 inhibition over placebo or standard of care, with low treatment effect heterogeneity: I 2 0% (95% CI: 0, 53%). Meta-regression showed no evidence of treatment effect modification by patient characteristics. Trial-specific mortality rates were explained by known patient-level predictors of COVID-19 outcome (male sex, CRP, hypertension), and country-level COVID-19 incidence. Conclusions: IL-6 inhibition is associated with clinically meaningful improvements in outcomes for patients admitted with COVID-19. Long-term benefits of IL-6 inhibition, its effectiveness across healthcare systems, and implications for differing standards of care are currently unknown.

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