The combination of the neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as a novel predictor of intravenous immunoglobulin resistance in patients with Kawasaki disease: a multicenter study

Introduction: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been reported to be a predictor for intravenous immunoglobulin (IVIG) resistance in patients with Kawasaki disease (KD) recently. The objective of the present study was to elucidate the predictive validity of this new marker in a multicenter study. Materials and methods: We retrospectively reviewed the clinical records of 520 consecutive KD patients (development data set) and 332 subsequent patients (validation data set) at 7 hospitals in Japan. Results: Both NLR and PLR were significantly higher in the IVIG-resistant group than in the IVIG-responsive group. When we set the cut-off point as NLR ≥ 4.11 and PLR ≥ 119, multiple logistic regression analyses showed that a high NLR and PLR before initial IVIG were independent predictors of IVIG resistance, and their combination was a stronger predictor than either alone. The sensitivity and specificity of the combination of NLR ≥ 4.11 and PLR ≥ 119 were 0.58 and 0.73 in the development data set. Validated using an independent data set, they were 0.54 and 0.72 in the validation data set. On comparing the AUC of this predictor with those of the Gunma and Kurume scores, the AUC was highest for this predictor, followed by the Gunma score and Kurume score (0.70, 0.68, and 0.64, respectively). Discussion: The predictive validity of the combination of a high NLR and PLR, which is a simple and convenient indicator, was equal to or better than that of the existing scoring systems. The new predictive marker may be a suitable indicator for predicting IVIG resistance in KD patients.