American College of Rheumatology Provisional Criteria for Clinically Relevant Improvement in Children and Adolescents With Childhood‐Onset Systemic Lupus Erythematosus

To develop a Childhood Lupus Improvement Index (CHILI) as a tool to measure response to therapy in childhood‐onset systemic lupus erythematosus (cSLE), with a focus on clinically relevant improvement (CRIcSLE). Pediatric nephrology and rheumatology subspecialists (n = 213) experienced in cSLEmanagement were invited to define CRIcSLEand rate a total of 433 unique patient profiles for the presence/absence of CRIcSLE. Patient profiles included the following cSLEcore response variables (CRVs): global assessment of patient well‐being (patient‐global), physician assessment of cSLEactivity (MD‐global), disease activity index score (here, we used the Systemic Lupus Erythematosus Disease Activity Index), urine protein‐to‐creatinine ratio, and Child Health Questionnaire physical summary score. Percentage and absolute changes in these cSLE‐CRVs (baseline versus follow‐up) were considered in order to develop candidate algorithms and validate their performance (sensitivity, specificity, area under the receiver operating characteristic curve [AUC]; range 0–1). During an international consensus conference, unanimous agreement on a definition of CRIcSLEwas achieved; cSLEexperts (n = 13) concurred (100%) that the preferred CHILIalgorithm considers absolute changes in the cSLE‐CRVs. After transformation to a range of 0–100, a CHILIscore of ≥54 had outstanding accuracy for identifying CRIcSLE(AUC0.93, sensitivity 81.1%, and specificity 84.2%). CHILIscores also reflect minor, moderate, and major improvement for values exceeding 15, 68, and 92, respectively (all AUC≥0.92, sensitivity ≥93.1%, and specificity ≥73.4%). The CHILIis a new, seemingly highly accurate index for measuring CRIin cSLEover time. This index is useful to categorize the degree of response to therapy in children and adolescents with cSLE.