Methylprednisolone pulse and prednisolone for intensification of primary treatment in Kawasaki disease patients at high risk of treatment resistance: a multicenter prospective cohort study.

The purpose of this study is to determine whether adding intravenous methylprednisolone pulse (IVMP) to primary adjunctive prednisolone with intravenous immunoglobulin (IVIG) improves treatment resistance and coronary artery aneurysms (CAA) in patients with Kawasaki disease (KD) with a high risk of treatment resistance. This multicenter, prospective, observational study was conducted at 28 hospitals in Japan from October 2016 to June 2020. For patients predicted to be resistant to treatment based on a Kobayashi score ≥ 5 and total bilirubin ≥ 1.0 mg/dL, each hospital independently decided to add IVMP followed by prednisolone, prednisolone alone, or nothing to the primary IVIG therapy. In total, 2856 consecutive KD patients were enrolled; of these, 399 (14.0%) were predicted to be treatment resistant. Patients who were resistant to the primary treatment and required additional treatment comprised 59%, 20%, and 26% of the IVIG-alone group, IVIG-plus-prednisolone group, and IVIG-plus-IVMP group, respectively (P < .0001). The CAA incidence (Z score ≥ 2.5) at month 1 was similar among the treatment groups (6.7%, 4.8%, and 7.3%, respectively; P = .66). CAA occurred more frequently in patients who needed third- or later-line therapy.Conclusions: Primary adjunctive corticosteroid therapy improved the treatment response and suppressed inflammation. However, the study found no benefit of adding IVMP to prednisolone therapy. Patients receiving IVIG alone achieved coronary outcomes comparable to those of patients receiving primary adjunctive corticosteroid therapy although they were more likely to require additional rescue treatment. KD inflammation should be resolved no later than the third line of additional treatment to reduce the risk of CAA.Trial registration: University Hospital Medical Information Network Clinical Trials Registry in Japan ( https://www.umin.ac.jp/ctr/index.htm ) under code UMIN000024937.