The Feasibility of Japanese Histological Grade Classification for Predicting Renal Function Deterioration among Taiwanese Individuals with IgA Nephropathy

Abstract

Background: We aimed to validate the Japanese histological grading classification (JHGC) in our population of IgA immunoglobulin (IgAN) cases. Methods: We conducted a retrospective cohort study at Taichung Veterans General Hospital in Taiwan from January 2011 to December 2023. The process involved assessing JHGC’s clinical, histological, and merged grading system. Composite renal outcomes based on glomerular filtrate rate (eGFR) were considered. Results: The study included 359 IgAN by renal biopsies. Kidney function at the time of biopsy was suboptimal, with average SCr of 1.3 mg/dL, eGFR of 54.0 mL/min/1.732 m2, and urine protein–creatinine ratio (UPCR) of 1.2 mg/mg. JHGC effectively identified different severity levels of histological and clinical aspects in Taiwanese IgAN. Initial 4-histological classification showed significantly higher MEST-C scores (p p 2. The new grading system effectively differentiated risk factors for renal outcomes (log-rank p 2 and UPCR < 0.5 g/day group.

Keywords

• IgA nephropathy (IgAN)
• Japanese Histological Grade Classification (JHGC)
• composite renal outcome
• end-stage kidney disease (ESKD)
• Oxford classification
• glomerular filtration rate (GFR)