Among patients with admission C-reactive protein (CRP) levels of ≥20 mg/dL, denoting a significant inflammatory burden, corticosteroid treatment was associated with a 75–80% reduction in the composite severe outcome of MV and mortality (adjusted odds ratio (aOR), 0.23; 95% CI, 0.08–0.70), while, among those with CRP ≤10 mg/dL, corticosteroid treatment was associated with severe COVID-19 outcomes (aOR, 2.64; 95% CI, 1.39–5.03). The gene discussed is CRP; the disease is COVID-19.