Background: The risk of immunoglobulin resistance is still likely to occur in Kawasaki disease (KD) despite adequate treatment. The Kobayashi score (KS) is used to predict unresponsiveness to treatment although the usefulness of the score in populations other than Asian seems to be debatable.

Aim: The analysis of clinical and laboratory parameters predisposing to immunoglobulin resistance and coronary complica­tions in children hospitalised due to KD.

Methods: The data of children hospitalised due to KD between 2003 and 2016 underwent analysis. Clinical and laboratory parameters were analysed, including all parameters present in KS in relation to the risk of intravenous immunoglobulin (IVIG) resistance and the occurrence of coronary complications in the form of aneurysms and dilatations.

Results: Seventy-three children (51 boys; aged 1.5–135 months) with KD were hospitalised. In eight (11%) patients IVIG re­sistance was observed. We reported aneurysms or coronary dilatations in 13 (17.8%) children. The criterion for increased risk of IVIG resistance based on KS (≥ 4 points) was fulfilled by 21 (29%) children. Resistance to IVIG and coronary complications were observed in four (19.1%) and two (9.5%) children with the score ≥ 4 points, respectively, and four (7.7%) and 11 (21.6%) from the group < 4 points in KS, respectively. The prevalence of IVIG resistance and coronary artery complications was not different between the group with ≥ 4 and the group with < 4 points (p = 0.22, p = 0.32, respectively). A higher risk of IVIG resistance was confirmed in children with a longer duration of fever (13.0 days with IVIG resistance vs. 9.2 days with a good response to IVIG, p = 0.04). For the prediction of the occurrence of coronary artery aneurysms the following were of great importance: the day of diagnosis (which was usually the day of the beginning of treatment), the number of symptoms, and the maximal platelet count (p = 0.001; p = 0.019 and p = 0.026, respectively).

Conclusions: In our study population we did not demonstrate the usefulness of KS to predict IVIG resistance or the risk of the occurrence of coronary artery aneurysms. However, prolonged fever, late diagnosis, poorly symptomatic course of the disease, and a high platelet count at the time of the follow-up remain independent risk factors.