[Validity of the infectious disease surveillance system on comparison of nationwide surveys of Kawasaki disease during a 10 year period]

Abstract

Purpose: To verify the validity of the infectious disease surveillance system in Japan using data for Kawasaki disease.

Materials and methods: Data from nationwide surveys of Kawasaki disease conducted by the Kawasaki Disease Research Committee every two years over the 10 years (120 months) from 1989 through 1998 were used to calculate a gold standard. Then, the monthly numbers of patients with Kawasaki disease reported by monitoring hospitals (about 550 hospitals) to the surveillance system were compared with this gold standard. Each of the monthly numbers was standardized by division by the average monthly number of patients over the 120 months. Observations for 3 districts (eastern part, central part, and western part of Japan) were conducted as well as for the whole country.

Results: The number of patients reported to the surveillance system varied more widely than in the nationwide survey, but directions of the fluctuations were similar to the chronologic changes in nationwide numbers. Accordingly, a high correlation coefficient value of 0.794 was obtained (p < 0.01). Similar results were observed in all 3 districts. The correlation coefficients were 0.709 for the eastern part, 0.561 for the central part, and 0.712 for the western part, respectively, and all of them were of statistically significant.

Conclusion: Changes in number of patients with Kawasaki disease reported to the surveillance system resemble the pattern of the gold standard.