A new study suggests that the incidence of Kawasaki syndrome (KS)—an acute febrile illness of unknown etiology—has not markedly changed in the United States over the past decade. KS usually strikes children under the age of 5 and is more common among boys and people of Asian descent. Children are typically hospitalized after they develop a fever, red eyes and lips, strawberry tongue, rash, and swollen lymph nodes. If KS is not diagnosed and treated rapidly with intravenous gamma globulin, it can result in heart damage and death.
Robert Holman, M.S., of the Centers for Disease Control and Prevention, along with other colleagues at the CDC and Claudia A. Steiner, M.D., M.P.H., of the Center for Delivery, Organization, and Markets, Agency for Healthcare Research and Quality, analyzed hospital discharge records from the 1997 and 2000 Kids' Inpatient Database (a large national all-payer database of pediatric hospital discharges) to identify children with a KS diagnosis. They weighted these KS discharges to estimate the number and rate of KS-associated hospitalizations for the United States.
In 2000, about 4,248 hospitalizations associated with KS occurred in the United States, and the median age of patients at admission was 2 years. Children under 5 years of age accounted for 3,277 of these KS hospitalizations (77 percent), and there was a KS hospitalization rate of 17.1 per 100,000 children. This rate was similar to the 1997 rate of 17.6 per 100,000 children. These rates are similar to estimates in other U.S. studies for the late 1980s and 1990s, suggesting that incidence rates haven't changed much. This is in contrast to Japan—which has the highest annual incidence of KS in the world, with 112 cases per 100,000 children—where KS incidence reportedly has increased by more than 1.5 times between 1987 and 1998.
Among U.S. children younger than age 5 in 2000, the rate of KS hospitalizations was highest among Asian and Pacific Islander children, followed by the rate for black children (39 and 19.7 per 100,000 children, respectively). No deaths associated with KS were reported among hospitalized children.
See "Kawasaki syndrome hospitalizations in the United States, 1997 and 2000," by Robert C. Holman, M.S., Aaron Y. Curns, M.P.H., Ermias D. Belay, M.D., and others, in the September 2003 Pediatrics 112(3), pp. 495-501.
Reprints (AHRQ Publication No. 04-R002) are available from the AHRQ Publications Clearinghouse and AHRQ InstantFax.