Validation of the Lupus Nephritis Clinical Indices in Childhood-Onset Systemic Lupus Erythematosus

Mina, R.; Abulaban, K.; Klein-Gitelman, M. S.; Eberhard, B. A.; Ardoin, S. P.; Singer, N.; Onel, K.; Tucker, L.; O'Neil, K.; Wright, T.; Brooks, E.; Rouster-Stevens, K.; Jung, L.; Imundo, L.; Rovin, B.; Witte, D.; Ying, J.; Brunner, H. I.

Arthritis Care Res (Hoboken). 2015 Jul 28; 68(2):195-202

Abstract

OBJECTIVE: To validate clinical indices of lupus nephritis activity and damage when used in children against the criterion standard of kidney biopsy findings. METHODS: In 83 children requiring kidney biopsy, the Systemic Lupus Erythematosus Disease Activity Index renal domain (SLEDAI-R), British Isles Lupus Assessment Group index renal domain (BILAG-R), Systemic Lupus International Collaborating Clinics (SLICC) renal activity score (SLICC-RAS), and SLICC Damage Index renal domain (SDI-R) were measured. Fixed effects and logistic models were calculated to predict International Society of Nephrology/Renal Pathology Society (ISN/RPS) class; low-to-moderate versus high lupus nephritis activity (National Institutes of Health [NIH] activity index [AI]) score: 10; tubulointerstitial activity index (TIAI) score: 5; or the absence versus presence of lupus nephritis chronicity (NIH chronicity index) score: 0 versus >/=1. RESULTS: There were 10, 50, and 23 patients with ISN/RPS class I/II, III/IV, and V, respectively. Scores of the clinical indices did not differentiate among patients by ISN/RPS class. The SLEDAI-R and SLICC-RAS but not the BILAG-R differed with lupus nephritis activity status defined by NIH-AI scores, while only the SLEDAI-R scores differed between lupus nephritis activity status based on TIAI scores. The sensitivity and specificity of the SDI-R to capture lupus nephritis chronicity was 23.5% and 91.7%, respectively. Despite being designed to measure lupus nephritis activity, SLICC-RAS and SLEDAI-R scores significantly differed with lupus nephritis chronicity status. CONCLUSION: Current clinical indices of lupus nephritis fail to discriminate ISN/RPS class in children. Despite its shortcomings, the SLEDAI-R appears best for measuring lupus nephritis activity in a clinical setting. The SDI-R is a poor correlate of lupus nephritis chronicity.

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