ABSTRACT: OBJECTIVE:Childhood-onset systemic lupus erythematosus (SLE) is associated with high risk for organ damage, which may be mitigated by early diagnosis and treatment. We characterized health care utilization for youth in the year preceding SLE diagnosis compared to controls. METHODS:Using Clinformatics DataMart (OptumInsight) de-identified administrative data from 2000 to 2013, we identified 682 youth ages 10-24 years with new-onset SLE (?3 International Classification of Diseases, Ninth Revision codes for SLE 710.0, each >30 days apart), and 1,364 age- and sex-matched healthy controls. We compared the incidence of ambulatory, emergency, and inpatient visits 12 months before SLE diagnosis and frequency of primary diagnoses. We examined subject characteristics associated with utilization preceding SLE diagnosis. RESULTS:Youth with SLE had significantly more visits in the year preceding diagnosis than controls across ambulatory (incidence rate ratio [IRR] 2.48, P < 0.001), emergency (IRR 3.42, P < 0.001), and inpatient settings (IRR 3.02, P < 0.001). The most frequent acute-care diagnoses and median days to SLE diagnosis were: venous thromboembolism (313, interquartile range [IQR] 18-356), thrombocytopenia (278, IQR 39-354), chest pain (73, IQR 29.5-168), fever (52, IQR 17-166), and acute kidney failure (14, IQR 5-168). Having a psychiatric diagnosis prior to SLE diagnosis was strongly associated with increased utilization across all settings. CONCLUSION:Youth with SLE have high health care utilization throughout the year preceding SLE diagnosis. Examining variable diagnostic trajectories of youth requiring acute care preceding SLE diagnosis, and increased attention to psychiatric morbidity, may help improve care for youth with new-onset SLE.