Association between the timing of intravenous immunoglobulin treatment and severity of Kawasaki disease.

Objectives: The early administration of immunoglobulin in Kawasaki disease occasionally results in treatment failure. However, whether this is because severe cases are diagnosed and treated early or due to other factors remains unclear. In this study, we examined the timing of initial immunoglobulin administration and immunoglobulin resistance in cases classified by severity of illness.

Methods: This study was a single-hospital, retrospective cohort study of 608 patients who received immunoglobulin within 4 (Early-treatment group, n=225) or between 5 and 7 days (Late-treatment group, n=383) following treatment onset. Cases were classified into four groups: high (n=55), moderate (n=96), low (n=197), and very-low (n=260) risk, based on the Kobayashi score, modified to exclude the day of illness factor. Within each risk group, immunoglobulin resistance was compared between the early- and late-treatment groups.

Results: The early-treatment group showed greater immunoglobulin-resistance than the late-treatment group. After severity classification, the cases of high and moderate-risk in the early-treatment group were more immunoglobulin-resistant than in late-treatment group, with odds ratios (95% CI) of 6.7 (1.6-28) and 3.7 (1.6-8.5), respectively. There was no difference in the low and very-low-risk groups.

Conclusion: Earlier illness day was a risk factor of immunoglobulin resistance in severe cases.