The Predictive Value of Fibrinogen-to-Albumin Ratio for Predicting Intravenous Immunoglobulin Resistance in Kawasaki Disease: A Prospective Cohort Study.

Background: Predicting resistance to intravenous immunoglobulin (IVIG) in the treatment of Kawasaki disease (KD) remains a focus of research. Fibrinogen and albumin in systemic inflammation play an important role. This study aims to investigate the predictive value of fibrinogen to albumin ratio (FAR) for initial IVIG resistance in patients with KD. Methods: The study prospectively recruited 962 patients with KD between July 2015 and June 2022. The serum characteristics of the two groups were compared by comparing fibrinogen and albumin, as well as other laboratory and clinical data between the IVIG-responsive and IVIG-resistant groups. Multivariate logistic regression was used to explore the relationship between FAR and IVIG resistance. Receiver operating characteristic (ROC) curves were used to determine the effectiveness of FAR in predicting initial IVIG resistance. Results: Our results demonstrated that IVIG-resistant patients had significantly higher fibrinogen levels (603.35 ± 99.00 mg/L), FAR (17.30 ± 3.31), and lower albumin (35.47 ± 5.24 g/L) compared to IVIG-responsive patients (fibrinogen 572.35 ± 145.75 mg/L; FAR 15.08 ± 4.32; albumin 38.52 ± 4.55 g/L). 15.20 was the best cut-off value of FAR for predicting initial IVIG resistance. The sensitivity was 72.5%, the specificity was 51.3%, the positive predictive value was 91.8%, and the negative predictive value was 20.0%. Multivariate logistic regression analysis, found that FAR was an independent predictor of initial IVIG resistance in KD children. Conclusions: The FAR was an independent risk factor for initial IVIG resistance, its predictive power for initial IVIG resistance exceeded that of albumin and fibrinogen alone. FAR may not be suitable as a single marker but might serve as a complementary laboratory marker to accurately predict initial IVIG resistance in KD.