Evaluation of Risk Factors of Coronary Artery Abnormalities in Incomplete Kawasaki Disease: An Analysis of Post RAISE.

Aim: The American Heart Association provides an algorithm for managing suspected incomplete Kawasaki disease (iKD), but the evidence remains limited. This study aimed to investigate the risk factors of coronary artery abnormalities (CAA) in iKD patients.

Methods: This study was a secondary analysis of Post RAISE, a prospective cohort study of Japanese KD patients. The primary analysis included patients treated within 10 days of onset. CAA was defined by a Z score of the coronary artery diameter ≥ 2.5. Multiple logistic regression analysis was used to identify independent risk factors of CAA 1 month after treatment commencement.

Results: Post RAISE enrolled 2628 KD patients, of whom 565 with iKD were included in the main analysis. Of the latter, 32 (5.7%; 95% confidence interval [CI]: 3.9-7.7) developed CAA 1 month after treatment commencement. The baseline factors significantly associated with CAA development on univariate analysis were young age (median: 10.8 vs. 20.8 months; p = 0.002), high platelet count (39.6 × 10⁴ vs. 33.5 × 10⁴/μL; p = 0.008), and pre-treatment presence of CAA (38 vs. 11%; p < 0.001). Multivariate analysis of the independent variables, including age ≤ 12 months, platelet count > 45 × 10⁴/μL, prednisolone use, and the pre-treatment presence of CAA, revealed a significant association of platelet count > 45 × 10⁴/μL (odds ratio: 3.46; 95% CI: 1.43-8.13) and the pre-treatment presence of CAA (4.62; 1.93-10.85) with the primary outcome.

Conclusions: A high platelet count and pre-treatment presence of CAA were risk factors of CAA development in iKD patients 1 month after treatment commencement.