Risk factors for coronary artery abnormalities and resistance to immunoglobulin plus ciclosporin A therapy in severe Kawasaki disease: subanalysis of the KAICA trial, randomized trial for cicrosporin A as the first-line treatment

Background To investigate risk factors for coronary arterial abnormalities (CAAs) and resistance to treatment in patients with Kawasaki disease (KD) receiving intravenous immunoglobulin (IVIG) plus ciclosporin A (CsA) as the first-line treatment, we performed a subanalysis of baseline data of participants in the KAICA trial, a phase 3, randomized study (JMA-ILA00174). Methods All data of the patients enrolled in the KAICA trial, who had a Gunma score ≥5 at diagnosis and had been randomly assigned to either IVIG (2 g/kg/24 h) plus CsA (5 mg/kg/day for 5 days) (n = 86) or IVIG alone (n = 87), were subjected to this study. CAA was defined by a Z score ≥2.5 observed within 4 weeks after treatment initiation. Baseline data including genotypes of KD susceptibility genes were compared between subgroups of patients for CAA or treatment response for each treatment group. Backword-forward stepwise logistic regression analyses were performed. Results Pre-Z-max, defined as the maximum among Z scores on four coronary artery branches before treatment, was higher in patients with CAA in both treatment groups and was associated with CAA in IVIG plus CsA treatment group [odds ratio (OR) = 17.0]. High serum total bilirubin level was relevant to treatment resistance only in the IVIG plus CsA group (OR = 2.34). Conclusions Coronary artery enlargement before treatment is a major determinant of CAA even in KD patients treated with initial IVIG treatment intensified by addition of CsA. Baseline serum total bilirubin level was a risk factor associated with resistance to IVIG plus CsA.