Background/Purpose: Patients with Kawasaki disease (KD) resistant to IVIG remain a challenge. IVIG resistance has been recognised as a risk factor for the development of coronary artery abnormalities (CAA). Prediction of IVIG resistance in Japanese patients has been successful with the Kobayashi and Egami scores. However, these scores lack sensitivity when applied to patients with KD outside of Japan. We aim to evaluate IVIG resistance, assess if it is a risk factor for CAA, and calculate the sensitivity and specificity of the Kobayashi and Egami scoring systems in predicting IVIG resistance in this single centre Canadian cohort treated with IVIG and low dose aspirin (ASA).

Methods: A retrospective chart review was performed for all patients diagnosed with KD and treated with at least one dose of IVIG (2 g/kg) and low dose ASA (< 10 mg/kg/day) between January 2004 and December 2014. Patients were excluded if they were transferred from another centre, if they had a significant structural cardiac defect not-related to KD, or if there was insufficient laboratory data to perform the Kobayashi and Egami scores. Demographic data, clinical criteria, coronary involvement, laboratory results, and doses of ASA and IVIG were recorded. IVIG resistance was defined as the requirement of a second dose of IVIG. Coronary arteries were considered abnormal if the dimension adjusted for body surface area and expressed in SD units had a z score > or equal to 2.5 at the 6 to 8 week echocardiogram. Sensitivity and specificity calculations were performed. P-values for categorical variables were calculated with the Chi-square test; Wilcoxon rank sum test for continuous variables.

Results: Of the 313 patients identified, 304 charts were reviewed and 262 patients met the inclusion criteria. There were 149 (56.8%) males; 113 (43.2%) females. The mean age was 3.3 years. Criteria for complete KD were met by 198 (75.6%) patients and 64 (24.4%) had incomplete KD. IVIG resistance was seen in 29.8% (78/262) of the study cohort. In patients with complete KD, the sensitivity of the Kobayashi and Egami scores was low at 33.3% and 31.7% respectively but the specificity was high at 79.3% and 83%. In incomplete KD, the sensitivity of the Kobayashi and Egami scores was also low at 26.7% and 40% respectively but again the specificity was high at 87.8% and 79.6%. From the study cohort, 21 out of 262 patients (8%) had CAA. There was a statistically significant increase in CAA in those who were IVIG resistant with 15 patients (19.2%) developing CAA in the IVIG resistant group compared to 6 patients (3.3%) in those who responded to one dose of IVIG (p<0.0001). IVIG resistant patients did not differ statistically from IVIG responders in regards to age, gender or duration of fever at diagnosis.

Conclusion: To our knowledge, this is the largest non-Japanese cohort that assesses the performance of both the Kobayashi and Egami scores. In this Canadian cohort, both failed to predict IVIG resistance. Patients with IVIG resistance had a significantly higher incidence of CAA. These results further highlight the need for the development of a new risk assessment tool for the prediction of IVIG resistance in North American children with KD so that risk stratification could be considered in future treatment strategies.

« Back to 2016 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-performance-of-the-kobayashi-and-egami-scores-in-detecting-ivig-resistance-in-kawasaki-disease-in-a-single-centre-canadian-cohort-treated-with-ivig-and-low-dose-aspirin/