Effectiveness of intravenous immunoglobulin therapy for invasive group A Streptococcus infection: A Japanese nationwide observational study

Abstract

Objectives: Invasive group A Streptococcus infection (iGAS) is a rare but fatal condition. We aimed to evaluate the effectiveness of intravenous immunoglobulin (IVIG) in the treatment of iGAS. Methods: Patients’ data were extracted from a Japanese nationwide database between April 2018 and March 2021. The primary outcome was in-hospital mortality rate, whereas the secondary outcomes were 30-day and 7-day mortality rates. Results: Overall, 481 patients (median age, 65 years; female, 49.7%) were included in the analysis. The overall mortality rate was 31.0%. After adjusting for background factors, we found that IVIG treatment had no effect on in-hospital mortality (adjusted odds ratio [OR]: 0.99, 95% confidence interval [CI]: 0.93-1.04, P = 0.92). Similar results were obtained after propensity score matching (OR: 1.00, 95% CI: 0.62-1.61, P >0.99). The 7-day and 30-day mortality rates were not associated with IVIG treatment. Conclusion: IVIG administration had no survival benefit in iGAS patients. However, these overall findings should not be extrapolated to streptococcal toxic shock syndrome as the effect of IVIG therapy in this condition remains uncertain. Considering the rarity of iGAS, conducting a randomized controlled trial may be impractical. Therefore, an equivalent or more extensive observational study is warranted to validate these findings.

Keywords

• Group A Streptococcus
• Intravenous immunoglobulin
• Streptococcal toxic shock syndrome
• Survival
• Mortality