Kawasaki disease (KD) is an acute childhood vasculitis that may result in coronary aneurysms. Treatment of KD with a single infusion of 2 gm/kg intravenous immunoglobulin (IVIG) is well established, but acetylsalicylic acid (ASA) dose remains controversial. Our primary objective was to determine the difference in the incidence of IVIG resistance between 2 ASA doses. Our secondary objective was to compare the duration of hospital stay and the incidence of coronary artery aneurysm.
We reviewed charts of patients with KD from 2 Canadian centers to assess the impact of ASA dose on IVIG resistance (operationally defined as administration of a second dose of IVIG). Both centers used standard IVIG dosing, but center 1 used low-dose ASA from diagnosis (3-5 mg/kg/day) while center 2 used initial high-dose ASA (80-100 mg/kg/day).
There were no significant differences in baseline characteristics between the 2 centers. Retreatment with a second dose of IVIG was required in 28 of 122 patients (23%) treated with low-dose ASA, and in 11 of 127 patients (8.7%) treated with high-dose ASA in center 1 and center 2, respectively (P = 0.003). After adjusting for confounders, low-dose ASA was associated with higher odds of IVIG resistance (OR 3.2 [95% confidence interval 1.1, 9.1]). The mean duration of hospital stay was 4.1 and 4.7 days, respectively (P = 0.37). Coronary artery aneurysms were seen in 2 of 117 and 6 of 125 patients from centers 1 and 2, respectively (P = 0.28).
Low-dose ASA was associated with 3-times higher odds of IVIG retreatment compared to high-dose ASA, with no significant difference in duration of hospital stay or incidence of coronary artery aneurysms.