Total and differential leukocyte counts are useful inflammatory
biomarkers. The ability of the neutrophil-to-lymphocyte ratio (NLR) to predict outcomes in patients with
Kawasaki disease (KD) was assessed in this study. All patients with KD who underwent consecutive complete blood count analyses during the acute febrile phase before
intravenous immunoglobulin (
IVIG), 2 days after
IVIG regardless of defervescence, and 3 to 4 weeks after defervescence were enrolled. NLR was calculated by dividing the neutrophil count by the lymphocyte count. NLR values that best predicted
IVIG resistance and the development of coronary artery abnormalities were determined by receiver-operating characteristic curve and multivariate analyses. Of the 587 patients with KD, 222 were
IVIG resistant.
IVIG-resistant patients had higher NLRs than
IVIG-responsive patients. The best NLR cut-off values during the acute febrile phase and 2 days after
IVIG for predicting
IVIG resistance were 5.49 (p <0.001) and 1.26 (p <0.001), respectively. Sixty-two patients developed coronary artery abnormalities; 47 had coronary dilatation, and 15 had
aneurysms. Patients with
aneurysms, but not patients with dilatation, had higher NLRs than patients without coronary artery abnormalities. The best NLR cut-off value 2 days after
IVIG for predicting
aneurysm development was 1.01 (p <0.001). Multivariate analysis revealed that the NLR 2 days after
IVIG independently predicted
coronary aneurysm development (p = 0.03) and
IVIG resistance (p <0.001). In conclusion, the NLR can be used for risk stratification in patients with KD. An NLR 2 days after
IVIG that exceeded 1 was predictive of
coronary aneurysm development and
IVIG resistance.