Effect of Intravenous Immunoglobulin for Fulminant Myocarditis on In-Hospital Mortality: Propensity Score Analyses

• Study on intravenous immunoglobulin (IVIG) for fulminant myocarditis.
• We performed propensity score analyses with the use of a nationwide database in Japan.
• IVIG for fulminant myocarditis was not associated with lower in-hospital mortality.
• The total costs were higher in IVIG users than in nonusers.

BackgroundFulminant myocarditis (FM) is a rare but life-threatening disease. Intravenous immunoglobulin (IVIG) is not recommended for acute or chronic myocarditis in Western nations owing to the lack of rigorous evidence, but it is widely used in other countries, including Japan. This nationwide retrospective cohort study focused on evaluating the effect of IVIG in FM patients.Methods and ResultsUsing the Diagnosis Procedure Combination database in Japan, we identified 603 FM patients aged ≥16 years who received mechanical circulatory support within 7 days after admission. We performed propensity score analyses to compare the in-hospital mortality and total costs between IVIG users (n = 220; 36.5%) and nonusers (n = 383; 63.5%). Among propensity score–matched patients (164 pairs), there was no significant difference in in-hospital mortality between IVIG users and nonusers (36.6% vs 37.2%; P = .909). A multivariable logistic regression analysis showed no significant association between IVIG use and in-hospital mortality (adjusted odds ratio 0.91; 95% confidence interval 0.52 to 1.58; P = .733). The median total costs were significantly higher for IVIG users than for nonusers (US $44,226 vs $33,280; P < .001).ConclusionIVIG for FM was not significantly associated with a decrease in in-hospital mortality.