Abstract
BACKGROUND: The revised 2018 ISN/RPS Classification System for lupus nephritis (LN) includes calculations for both activity index (A.I.) and chronicity index (C.I.). Unchanged were the thresholds of < 25%, 25-50%, and > 50% crescents to distinguish between mild, moderate, and severe activity/chronicity. We aimed to evaluate these thresholds for percent crescents in childhood-onset LN. METHODS: Eighty-six subjects < 21 years of age were enrolled from the pediatric glomerulonephritis with crescents registry, a retrospective multi-center cohort sponsored by the pediatric nephrology research consortium. thresholds of 10%, 25%, and 50% for both cellular fibrocellular and fibrous crescents were interrogated for primary outcomes of kidney failure, egfr, and egfr slope. results: median age at time of initial biopsy was 14 years (range 1-21). median follow-up time was 3 years (range 1-11). cumulative incidence of kidney failure was 6% at 1 year and 10% at latest follow-up. median egfr slope was - 18 ml 1.73 m(2) min (iqr - 51 to + 8) at 1 year and - 3 ml min 1.73 m(2) year (iqr - 19 to + 6) at latest follow-up. we found no difference in kidney failure at the proposed >< 25% and 25-50% cellular crescents thresholds, and thus added a new provisional threshold of 10% that better predicted outcomes in children. moreover, use of 10% and 25% thresholds for fibrous crescents showed a fourfold and sevenfold increase in risk of kidney failure. conclusions: in children with crescentic ln, use of 10% and 25% thresholds for cellular crescents better reflects disease activity, while these thresholds for fibrous crescents better discriminates kidney disease outcomes. a higher resolution version of the graphical abstract is available as supplementary information. nephrology association.>
