The role of age-specific N-terminal pro-brain natriuretic peptide cutoff values in predicting intravenous immunoglobulin resistance in Kawasaki disease: a prospective cohort study

Abstract Background The prediction of resistance to intravenous immunoglobulins (IVIG) is currently still one of the main research areas in Kawasaki disease (KD). Several studies have reported on the use of N-terminal pro-brain natriuretic peptide (NT-ProBNP) to this end. However, considering the age-dependency of NT-ProBNP levels, age- specific NT-ProBNP cutoff levels to predict IVIG resistance in KD might be more precise and should be evaluated. Methods A prospective cohort study with standardized data collection involving 393 KD patients aged 1 month to 125 months was conducted between June 2015 and April 2018. The demographic characteristics, clinical manifestations and laboratory data were compared between the patients responding to initial intravenous immunoglobulin (IVIG-response group) and those who did not (IVIG-resistance group). We further distinguished four subgroups according to patients’ age (< 1 year, 1–2 years, 2–6 years, > 6 years). The cutoff values of NT-ProBNP for the prediction of IVIG resistance overall and in the subgroups were obtained using receiver operating characteristic (ROC) analysis. Results In all KD patients, the level of NT-ProBNP was significantly higher in the IVIG-resistance compared to the IVIG-response group (P = 0.006). This findings was similar in the subgroups except for patients older than six years. The best cutoff values of NT-ProBNP to predict IVIG resistance were 3755 pg/ml for all KD patients, 3710 pg/ml, 2800 pg/ml, 2480 pg/ml for those aged 2–6 years, 1–2 years and < 1 year, respectively. The corresponding sensitivities were 44.0, 52.2, 50.0 and 75.0%, while the specifities were 84.1, 86.3, 77.9 and 71.8%, respectively. Conclusions NT-proBNP is a complementary laboratory marker for the prediction of IVIG resistance in KD patients, particularly for those younger than one year. Applying age-specific cutoff values is more precise than one value for all ages.