Mortality among patients with a history of Kawasaki disease: the third look. The Kawasaki Disease Follow-up Group.

Abstract

Background: Long-term prognosis of Kawasaki disease is still unclear.

Methods: In a cohort study, 6576 patients with Kawasaki disease were observed from their first medical encounter because of the disease through the end of 1994, or until death. Standardized mortality ratios (SMR) with 95% confidence intervals (CI) were calculated with vital statistics data of Japan used for the control.

Results: Of 6576 patients who met the eligibility criteria, 6550 (99.6%) were followed through either the end of the study or the date of death. Twenty patients (14 male, 6 female subjects) died during the study period; an overall SMR of 1.35 (95% CI 0.82-2.08) was calculated. The SMR was 1.45 (95% CI 0.79-2.44) for male subjects and 1.15 (95% CI 0.42-2.52) for female subjects. During the acute phase of the disease (the first 2 months after the first visit to hospital), the SMR was higher, particularly in male subjects (SMR 10.13, 95% CI 3.72-22.08). After the acute phase, however, both boys and girls had low SMR. Nine of the 20 deaths were caused by Kawasaki disease; there were three deaths as a result of congenital heart diseases and two subjects died of malignant neoplasms of lymphatic or hematopoietic tissues.

Conclusions: Although the mortality rate among those with a history of Kawasaki disease was elevated in Japan, many of the deaths that caused the elevation occurred during the acute phase of the disease. The mortality rate was not increased after the acute phase of the disease.