Does MEST-C score predict outcomes in pediatric Henoch-Schönlein purpura nephritis?

Background: Children with Henoch-Schönlein purpura nephritis (HSPN) have an increased risk of chronic kidney disease (CKD). Renal biopsy diagnostic of HSPN is graded using the International Study of Kidney Disease in Children criteria, which do not predict outcomes. The 2016 Oxford Classification's MEST-C scoring system predicts outcomes in adults with histologically identical IgA nephropathy, but evidence of its utility in pediatric HSPN is lacking. Our hypothesis was that MEST-C scores predict outcomes in children with HSPN.

Methods: A retrospective cohort analysis of data from 32 children with HSPN who underwent renal biopsy was performed. We used logistic regression and receiver operator characteristic curves to analyze the ability of MEST-C to predict the composite outcome of hypertension (blood pressure ≥ 95% for age/sex/height), CKD (estimated glomerular filtration rate < 90 mL/min/1.73 m), or proteinuria (urine protein-to-creatinine ratio > 0.2 mg/mg).

Results: The median age at diagnosis was 7.9 years (IQR 5.8, 11.7); 56% were male, 19% were Hispanic, and 9% were Black. After a median follow-up of 2.7 years, 38% of patients (n = 12) reached the outcome. S1 score was significantly associated with the outcome (OR 7.9, 95% CI 1.5-42.6). S1 accurately predicted the outcome (area under the curve 0.72, 95% CI 0.55-0.88) with 58.3% sensitivity and 85.0% specificity, indicating a positive predictive value of 70.0% and a negative predictive value of 77.3%.

Conclusions: S1 accurately predicted our composite outcome of hypertension, CKD, and proteinuria in a diverse cohort of U.S. children with HSPN. Further investigation is warranted to validate these findings.