Toward Integrated Use of BNP and N-Terminal Pro-B-Type Natriuretic Peptide (NT-ProBNP) in Predicting Resistance to Initial Intravenous Immunoglobulin (IVIG) in Acute Phase of Kawasaki Disease

B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) have been suggested as potential predictors of resistance to intravenous immunoglobulin (IVIG) in the acute phase of Kawasaki disease. However, these peptides are selectively and inconsistently measured across institutions, making their integrated use in outcome prediction challenging. This study analyzed data from two nationwide Korean Kawasaki disease surveys (2012–2014 and 2015–2017), including 18,110 patients. Of these, 12,537 had BNP or NT-proBNP results (group 1), while 5,573 did not (group 2). Log-transformed BNP and NT-proBNP values were standardized into z scores within their respective subgroups. Propensity score matching and logistic regression analyses were performed to assess their predictive value for resistance to initial IVIG. The z scores of log-transformed values remained significant in multivariate analyses (P = 0.002 for BNP, P = 0.026 for NT-proBNP). In univariate analyses, both BNP and NT-proBNP were significant predictors of IVIG resistance, with Nagelkerke R2 values of 0.029 and 0.015, respectively. After log transformation, the values converged to 0.024 and 0.025. The similarity in predictive power supports a common scale for these markers. The z scores of log-transformed BNP and NT-proBNP values demonstrated comparable predictive performance for resistance to initial IVIG, supporting the potential feasibility of their integrated use in clinical research and practice.