Kawasaki syndrome and risk factors for coronary artery abnormalities - United States, 1994-2003

Background: Kawasaki syndrome (KS) causes significant morbidity among children in the United States and other countries and can result in a range of cardiac and noncardiac complications. Methods: To describe the occurrence of KS in the United States and risk factors for the development of coronary artery abnormalities (CAA), national KS surveillance data were analyzed for patients with KS onset during 1994-2003. The surveillance is a passive system, and information is collected on a standardized case report form. Results: During 1994 through 2003, 3115 patients who met the KS case definition were reported to the national KS surveillance system. The median age of KS patients was 32 months; the male-female ratio was 1.5:1. Nearly one-third (31.8%) of the cumulative number of KS cases occurred during January through March. During the study period, 362 (12.9%) of 2798 KS patients had CAA. The proportion of patients with CAA increased from 10.0% in 1994 to 17.8% in 2003. Age younger than 1 year and 9-17 years, male sex, Asian and Pacific Islander race and Hispanic ethnicity (a previously unidentified risk factor) were significantly associated with the development of CAA. Conclusions: The increase in CAA was attributed to widespread use of the criteria of de Zorzi et al, resulting in increased recognition of coronary artery dilatations. The factors contributing to a higher risk of CAA, such as delayed treatment, particularly among Hispanics, need to be investigated.