Corticosteroids as adjunctive therapy to standard treatment in Kawasaki disease: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials.
UNLABELLED: Kawasaki disease (KD) is an acute systemic vasculitis and the leading cause of acquired heart disease in children in developed countries. While IVIG plus aspirin remains standard treatment, 10-20% of patients are IVIG-resistant and face an elevated risk of coronary artery abnormalities. Corticosteroids have been explored as adjunctive therapy, though evidence on their benefit remains inconsistent. To assess the efficacy and safety of adjunctive corticosteroids in Kawasaki disease across key clinical outcomes. This PRISMA 2020-compliant systematic review and meta-analysis included RCTs identified through database searches up to April 2026. Risk of bias was assessed using Cochrane RoB 2.0. Data were pooled using random-effects models to estimate risk ratios (RRs) and mean differences (MDs) with 95% CIs. Subgroup analyses, leave-one-out sensitivity analyses, and GRADE certainty appraisal were also performed. Eight studies (n = 4106) were included. No significant differences were found in coronary artery abnormalities (CAA) within 1 month (RR 0.49, 95% CI 0.17-1.42), after 1 month (RR 0.81, 95% CI 0.43-1.55), fever duration (MD - 1.75, 95% CI - 3.71 to 0.21), or adverse events (RR 1.08, 95% CI 0.57-2.07). Hospital stay was modestly shorter with corticosteroids (MD - 0.99, 95% CI - 1.86 to - 0.11). Exploratory subgroup analyses suggested potential benefits with prednisolone-based and prolonged corticosteroid regimens for selected outcomes; however, these findings should be interpreted cautiously given multiple subgroup comparisons. Overall certainty of evidence was very low. CONCLUSION:  Adjunctive corticosteroids did not significantly improve major outcomes in KD. Prednisolone-based regimens showed some promise, but high-quality trials are still needed before any firm conclusions can be drawn. WHAT IS KNOWN: • Corticosteroids have been studied as adjunctive therapy for Kawasaki disease, but their effects on coronary outcomes and other clinical outcomes remain inconsistent. WHAT IS NEW: • This meta-analysis found no significant improvement in major outcomes with adjunctive corticosteroids, although prednisolone-based and prolonged regimens may provide benefits for selected outcomes.