Kawasaki disease in Spanish paediatric population and synoptic weather types: an observational study.

Kawasaki disease (KD) is a vasculitis of unelucidated pathogenesis that usually occurs in paediatric patients. In this study we analyse the temporal pattern and geographical distribution of the disease in Spain, and its relationship with atmospheric circulation patterns. We performed a retrospective study in which we collected all hospital admissions due to KD in the country between 2005 and 2015 and explored their relationship with demographic and geographical characteristics. Moreover, we calculated daily surface atmospheric patterns over Spain to study the relationship between weather types (WT) and KD Admissions. The average admission rate for KD in the paediatric population was 3.90 per 100,000, with a male to female ratio of 1.56:1. The highest rate of admissions was found in the 0-4-year-old group, with an incidence of 11.7 cases per 100,000. Admissions followed an annual cyclic pattern with a peak of incidence in January (p = 0.022) and a nadir in September. There was an upwards trend in the number of KD admissions in male sex during the study period (p = 0.004). However, there were marked geographical differences in the incidence rate. Finally, the analysis of the relationship between the WT and the number of admissions by KD revealed no statistically significant association. KD admissions follow a peculiar seasonal and spatial distribution, that suggest the involvement of environmental factors in the disease; however, the absence of an association with WT should be interpreted with caution and regional studies should be done to explore this relationship.