Abstract: Background: Timely diagnosis of Kawasaki disease (KD) still posed a big challenge especially for those presenting atypical forms. Objective: To analyze the risk factors for delayed diagnosis of KD. Design: Case-control study. Methods: KD diagnostic criteria of Kawasaki Disease Research Committee of Japan (5th Edition, 2005) were adopted. KD can be diagnosed if more than 5 of the 6 main diagnostic criteria are met. KD inpatients were enrolled from Children's Hospital of Zhejiang University Medical College from January 2009 to Decemeber 2014. Patients diagnosed with KD more than 10 days after onset were included in the delayed diagnosis group, otherwise they were included in the non-delayed diagnosis group. The demographic features, clinical manifestations, total fever duration, the first laboratory examination results, and the first routine blood test after IVIG treatment were collected. Risk factors were established by univariate analysis and multivariate logistic regression analysis. Hosmer and Lemeshow test was used to test the goodness of the fit of risk factors. Main outcome measures: Risk factors for delayed diagnosis of KD. Results: There were 1,354 males and 840 females in 2,194 children with KD. The median age of onset was 21 (11-43) months. There were 168 cases enrolled in delayed diagnosis group. Compared with the non-delayed diagnosis group, the proportion of male and > 5 years old in the delayed diagnosis group were higher, the total fever duration was longer, the number of children who met the main diagnostic criteria was less, and the proportion of atypical KD children was higher, the levels of ALB and serum sodium were higher,the levels of ALT, TBiL and GGT were lower, the incidence of coronary artery injury was higher, the level of CRP, the absolute value and percentage of neutrophil and NLR before and after IVIG treatment were lower. The differences were statistically significant. The OR values of the total fever duration ≥10 days was 36.1(95% CI: 9.7-133.8), and the OR value of the cases meeting main diagnostic criteria was 0.40(95%CI：0.29~0.54). Conclusion: The risk factors for delayed diagnosis of KD were that the total fever duration was more than ten days and the number of main diagnostic criteria was less than five.

Key words: Kawasaki disease, Delayed diagnosis, Risk factor