Epidemiology of immunoglobulin resistant Kawasaki disease: results from a large, national database.

Few data exist evaluating the epidemiology of Kawasaki disease (KD) resistant to intravenous immunoglobulin (IVIG) in the United States on a national level, and characterization of the epidemiology of IVIG resistance may improve patient care. We aim to characterize the incidence of KD resistant to IVIG therapy and risk factors for resistance in children's hospitals in the United States. A large, administrative database was used to identify pediatric patients admitted with an ICD-9 code for mucocutaneous lymph node syndrome (446.1) and a charge for at least one dose of IVIG. Patients were identified as resistant to IVIG therapy if there were ≥2 calendar days between an initial IVIG dose and a subsequent dose of IVIG, methylprednisolone, rituximab, or infliximab. Patient demographic and hospital information were collected, as well as the charges for imaging, laboratory, and medications. Resistance occurred in 16.3% (hospital range 8.0-26.8%) of the population and was not associated with time or number of patients admitted with KD. Patients admitted to hospitals in the highest quartile of resistance were more likely to be African-American (26.5 vs 20.1%, p < 0.01), less likely to have an echocardiogram performed (93.6 vs 97.1%, p < 0.01), were more likely to have a C-reactive protein drawn (93 vs 79.9%, p < 0.01), and were less likely to have an erythrocyte sedimentation rate drawn (87.9 vs 91.6%, p < 0.01). The incidence of KD resistant to IVIG is highly variable among pediatric hospitals and treatment patterns vary between hospitals with high- and low-resistance patterns. Further evaluation of diagnostic and treatment patterns at pediatric hospitals is warranted.