Novel Index Developed to Measure Therapeutic Response in Childhood-Onset SLE

A novel and methodologically stringent index for the measurement of global improvement or therapeutic response in patients with childhood‐onset systemic lupus erythematosus (cSLE), called the Childhood Lupus Improvement Index (CHILI), has been developed, according to a study published in Arthritis Care & Research.

The study was designed to develop CHILI as a tool for measuring therapeutic response in cSLE, with a focus on clinically relevant improvement. Thirteen nephrology and rheumatology subspecialists with experience in cSLE management who were voting participants at an international Consensus Conference rated 200 of 433 unique patient profiles for the absence or presence of clinically relevant improvement in cSLE. Afterwards, these experts, along with 200 pediatric rheumatologists, were asked to rate 50 randomly selected profiles from the pool of 433. Data in these profiles included cSLE core response variables, including global assessment of patient well‐being, physician assessment of cSLE activity, disease activity index score (Systemic Lupus Erythematosus Disease Activity Index), urine protein‐to‐creatinine ratio, and Child Health Questionnaire physical summary score. Baseline vs follow-up percentage and absolute changes of cSLE core response variables were used to develop candidate algorithms and validate their performance (specificity, sensitivity, and area under the receiver operating characteristic curve [AUC; range: 0‐1]).

Unanimous agreement on a definition for clinically relevant improvement for cSLE was achieved at the international consensus conference, with all 13 specialists concurring that the preferred CHILI algorithm considers absolute changes of the cSLE core response variables. In a range from 0 to 100, a CHILI score of ≥54 was shown to have outstanding accuracy in the identification of clinically relevant improvement in cSLE (AUC=0.93; sensitivity=81.1%; specificity=84.2%). Furthermore, CHILI scores also reflect major, moderate, and minor improvement at values exceeding 92, 68, and 15 (AUC ≥0.92, sensitivity ≥93.1%; specificity ≥73.4%; for all).

Limitations for this study included an inability to test whether other disease activity indices would have identified clinically relevant improvement in cSLE; a lack of consensus on definitions of minor, moderate, and major improvement parameters; and a focus on the majority rule, which might have introduced bias.

Study investigators concluded that the “provisional CHILI instrument can be used to help identify children with cSLE who have experienced a clinically relevant improvement and to categorize the degree of improvement as minor, moderate, or major. However, additional testing in independent data-sets is required to confirm the performance characteristics of the CHILI when used in cSLE.”

Reference

Brunner HI, Holland MJ, Beresford MW, et al. The American College of Rheumatology Provisional criteria for clinically relevant improvement in children & adolescents with childhood‐onset systemic lupus erythematosus [published online January 25, 2019]. Arthritis Care Res. doi: 10.1002/acr.23834