Differential effect of corticosteroid treatment on Influenza, SARS, MERS, and SARS-CoV-2 patients: A meta-analysis and systematic review

BackgroundCorticosteroid has been used to manage inflammation caused by many diseases including respiratory viral infections. Many articles are available to support the good and bad side of this steroid use but remain inconclusive. To find some evidence about the safety of the drug, we investigated the effect of corticosteroids on the mortality of patients with respiratory viral infections including SARS-CoV-2, SARS, MERS, and Influenza. MethodWe searched articles in PubMed, Scopus, Cochrane, Medline, Google Scholar, and Web of Science records using keywords "corticosteroid" or "viral infection" or "patients" or "control study". Mortality was the primary outcome. ResultOur selected 24 studies involving 16633 patients were pooled in our meta-analysis. Corticosteroid use and overall mortality were not significantly associated (P=0.176), but in subgroup analysis, corticosteroid use was significantly associated with lower mortality in the case of SARS (P=0.003) but was not significantly associated with mortality for Influenza (H1N1) (P=0.260) and SARS-CoV-2 (P=0.554). Further analysis using study types of SARS-CoV-2, we found that corticosteroid use was not significantly associated with mortality in the case of retrospective cohort studies (P=0.256) but was significantly associated with lower mortality in the case of randomized control trials (P=0.005). Our findings uncover how the outcome of particular drug treatment for different diseases with comparable pathogenesis may not be similar and, RCTs are sometimes required for robust outcome data. ConclusionAt the beginning of the COVID-19 pandemic, data of corticosteroid use from other viral infections along with COVID-19 observational and retrospective cohort studies created confusion of its effect, but randomized control trials showed that corticosteroid can be used to treat COVID-19 patients.