Agreement between biopsy and renal function in pediatric patients with lupus nephritis. A retrospective study

ABSTRACT Introduction: Lupus nephritis (LN) is a consequence of Systemic Lupus Erythematosus (SLE). Renal biopsy is a potential prognostic biomarker for renal function. Objective: To correlate histopathological findings and renal function in children with LN. Materials and methods: A retrospective observational study was conducted on children with a histopathological diagnosis of NL. Patients with no follow-up registered were excluded. The kidney biopsy at diagnosis was evaluated using the ISN/RPS scale. The Kappa index was used to determine the level of agreement between renal failure (Glomerular Filtration Rate [GFR] < 60 mL/min/1.73 m2) and presence or absence of each index on the modified ISN/RPS scale. Results: A total of 57 patients with NL were treated from 2011 to 2018 at the institution. Of these, 40 (70%) met inclusion criteria, and 10 (25%) were male. The median age of NL diagnosis was 12.9 years (IQR, 11.1-14.9). Follow-up time was 2.3 years (IQR, 1.0-5.16). At diagnosis, karyorrhexis was the characteristic with highest level of agreement with renal failure (k = 0.1873 SE = 0.0759 P = .0068) and at the last follow-up, it was global segmental sclerosis (k = 0.1481 SE = 0.078 P = .0287). There was no difference in the GFR at the last follow-up and the presence of proteinuria at diagnosis (P = .3936). Conclusion: Renal biopsy findings may be an insufficient tool to predict renal function. Treat ment and prognosis of patients with NL should be done using other biomarkers and clinical signs. Prospective studies should be performed to confirm this hypothesis.