Kawasaki disease at the extremes of the age spectrum

We sought to determine outcomes of Kawasaki disease (KD) and to explore factors associated with poor clinical outcomes for patients diagnosed outside the age range of 1 to 4 years.

A retrospective review of data for all patients seen between January 1990 and April 2007 was performed. Patients were stratified into 5 groups on the basis of age at diagnosis.

A total of 1374 patients were identified; 61 (4%) were <6 months of age at diagnosis, 114 (8%) 6 months to <1 year, 854 (62%) 1 to 4 years, 258 (19%) 5 to 9 years, and 87 (6%) >9 years. Patients <1 year of age and those >9 years of age were more likely to have coronary artery abnormalities than were patients diagnosed between 1 and 4 years of age. Patients diagnosed between the ages of 5 and 9 years were at the lowest risk. Patients at both extremes of the age spectrum were more likely to present with <4 of the classic KD features, but only those <6 months or >5 years of age were at increased risk of being diagnosed >12 days after illness onset. Patients <6 months of age had lower albumin levels, and those <1 year of age had higher white blood cell and platelet counts, all of which are known predictors of coronary artery abnormalities. Patients >9 years of age were less likely to receive intravenous immunoglobulin treatment.

Outcomes for children diagnosed with KD at either extreme of the age spectrum are suboptimal, although the associated factors are different.