Abstract
BACKGROUND: Corticosteroids are commonly used as adjuvant therapy for acute respiratory distress syndrome by many clinicians because of their perceived anti-inflammatory effects. However, for patients with severe viral pneumonia, the corticosteroid treatment is highly controversial. OBJECTIVES: The purpose of this review is to systematically evaluate the effect and potential mechanism of corticosteroid administration in pandemic viral pneumonia. SOURCES: We comprehensively searched all manuscripts on corticosteroid therapy for influenza, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and SARS coronavirus 2 (SARS-CoV-2) viral pneumonia from the PubMed, EMBASE, Web of Science and Cochrane Library databases. CONTENT: We systematically summarized the effects of corticosteroid therapy for pandemic viral pneumonia and the potential mechanism of action for corticosteroids in coronavirus disease 2019 (COVID-19). IMPLICATIONS: Observational studies showed that corticosteroid treatment was associated with increased mortality and nosocomial infections for influenza and delayed virus clearance for SARS-CoV and MERS-CoV. Limited data on corticosteroid therapy for COVID-19 were reported. Corticosteroids were used in about a fifth of patients (670/2995, 22.4%). Although clinical observational studies reported the improvement in symptoms and oxygenation for individuals with severe COVID-19 who received corticosteroid therapy, case fatality rate in the corticosteroid group was significantly higher than that in the non-corticosteroid group (69/443, 15.6% versus 56/1310, 4.3%). Compared individuals with non-severe disease, those with severe disease were more likely to receive corticosteroid therapy (201/382, 52.6% versus 201/1310, 15.3%). Although there is no evidence that corticosteroid therapy reduces mortality in people with COVID-19, some improvements in clinical symptoms and oxygenation were reported in some clinical observational studies. Excessive inflammatory response and lymphopenia might be critical factors associated with severity of and mortality from COVID-19. Sufficiently powered randomized controlled trials with rigorous inclusion/exclusion criteria and standardized dose and duration of corticosteroids are needed to verify the effectiveness and safety of corticosteroid therapy.