Kawasaki Disease and Exposure to Fine Particulate Air Pollution.

OBJECTIVE: To analyze associations of short-term exposure to fine particulate matter (diameter ≤ 2.5 µm [PM2.5]), a measurable component of urban pollution, with the event date of fever onset for patients with Kawasaki disease (KD) residing in 7 metropolitan regions. STUDY DESIGN: A case-crossover study design was used. Time trends, seasonality, month, and weekday were controlled for by matching. We assembled PM2.5 exposure measurements from urban monitors and imputed PM2.5 to provide day-to-day temporal variability and resolution for time series indexes of exposures. Selected exposure windows (to 14 days) of PM2.5 were examined. RESULTS: A total of 3009 KD events were included for which the subject resided within a study metropolitan area and the event date occurred during years with available PM2.5. The estimated ORs (with 95% CIs) of an event of KD associated with a 10 µg/m(3) PM2.5 lagged moving average concentration of lagged exposure period (ie, concurrent, preceding day[s]) revealed no evidence of a consistent, statistically significant, positive association between elevated PM2.5 exposure and increased risk of KD. Extended analysis with stratification by city, sex, age, ethnic origin, incomplete or complete clinical manifestations, the presence of coronary aneurysm, and intravenous immunoglobulin resistance did not provide evidence of a consistent, statistically significant, positive association between elevated exposure to PM2.5 and increased risk of KD for any of the strata studied. CONCLUSIONS: This multicity study failed to establish a risk of the event of KD with short-term fine particulate exposure. Our negative findings add to the growing field of environmental epidemiology research of KD.

The Harada score in the US population of children with Kawasaki disease.

OBJECTIVE: To describe and quantify the presentations of Kawasaki disease (KD) in a children's hospital over 10 years to assess the Harada score in a US population. METHODS: A retrospective chart review from 2001 to 2011 of children discharged from Cleveland Clinic with the diagnosis of KD. Demographic and clinical data were collected and Harada scores were derived to evaluate efficacy in predicting risk for coronary artery aneurysms (CAAs). RESULTS: A total of 105 children met diagnostic criteria for KD, and 97 of 105 had long-term follow-up. Full criteria for KD were found in 67 of 105 (64%); 38 had incomplete presentations. CAA developed in 10 children, 5 during follow-up despite treatment with intravenous immunoglobulin (IVIG.) Children with incomplete presentations had a higher risk of developing CAA (20% vs 5%, P = .03) and a delayed diagnosis (median days from fever to diagnosis 8.0 vs 5.0 days, P < .001). Of children who developed CAA, 9 of 10 had a positive Harada score (sensitivity of 90%). All children who developed CAA after IVIG were in the high-risk group, but 1 child with an incomplete presentation who had a CAA at presentation was missed by the score. Overall, the negative predictive value was 98%. CONCLUSIONS: As in Japanese studies, a positive Harada score in a US population could be used to identify a high-risk population for CAA development. All children who developed CAA after treatment with IVIG would have been assigned to a high-risk category. Though not specific enough to select initial therapy, the score might be useful in identifying high-risk children for evaluation of new therapies and more frequent follow-up.