SAN DIEGO — Preliminary results from an ongoing surveillance of Kawasaki disease in the United States suggest that no unusual increases in cases occurred between 1998 and 2003, Ryan Maddox reported in a poster session at an international Kawasaki disease symposium.
“For the most part, the findings were consistent with those of previous studies and in line with what we'd expect,” Mr. Maddox, an epidemiologist with the division of viral and rickettsial diseases at the Centers for Disease Control and Prevention, Atlanta, told Rheumatology News. “We're not seeing more cases reported, which is a good sign.
He was quick to point out that while the study involved patients in 29 states, 80% of the data came from clinicians in just four states: California, Illinois, Michigan, and Virginia. “Obviously, we can't make a claim about [nationwide] incidence based on that,” Mr. Maddox said, but added that a new case reporting form was available online (www.cdc.gov\ncidod\diseases\kawasaki\index.htm
Between 1998 and 2003, 1,854 cases of Kawasaki disease were reported, which represents an estimated 10% of Kawasaki disease patients nationwide. Most patients (79.9%) were younger than 5 years, and 59.8% were boys. Overall, 57.7% were white, 19% were black, 17.7% were Asian or Pacific Islander, and the rest had other ethnic backgrounds.
Nearly all the patients (99%) were hospitalized for their disease, and 97.8% received intravenous immunoglobulin. Coronary artery abnormalities were reported in 14.7% of patients, which is higher than the 10.3% reported in a surveillance study conducted between 1991 and 1993. Reasons for this increase may have to do with improved ways to detect coronary artery abnormalities since the earlier study.
“It appears that [the prevalence of] aneurysms remained fairly constant over this period,” Mr. Maddox said. “However, [coronary] dilatations have been increasing. That's something that can be picked up through echo testing, which may be better at detecting these dilatations [than before.] That could account for at least some of the increase we're seeing.”
The investigators also observed that 23.2% of patients had illness onset in February or March, while 12.4% had onset in August or September. “Some people suggest [Kawasaki disease] is a virus,” said Mr. Maddox, “It could be this disease occurs because the virus is more prevalent during February and March. However, this disease does occur year-round.”