1422 Exploring BAFF, APRIL, and clinical characteristics in IgA nephropathy: a decade-long study in the Bulgarian population

Abstract Background and Aims IgA nephropathy (IgAN) represents a significant global health concern, contributing substantially to chronic kidney disease and renal failure. Despite its widespread impact, the Bulgarian population lacks comprehensive epidemiological data and specific biomarkers for IgAN. This decade-long retrospective study, conducted at a tertiary Nephrology Clinic in Bulgaria, aims to explore the clinical characteristics and serum levels of BAFF and APRIL in biopsy-confirmed IgAN patients and healthy controls. Method The study includes 125 biopsy-confirmed IgAN patients and 30 healthy controls. Notably, 70.4% of IgAN patients were male, with an average age of 35.94 ± 11.91 years. Baseline characteristics reveal advanced disease stages at diagnosis, possibly linked to delayed biopsy (24.22 ± 32.9 months from initial symptoms) and the absence of a screening program. Analyses of serum biomarkers (C3, BAFF, and APRIL) are conducted to identify any significant variations between IgAN patients and healthy volunteers. Results The average baseline estimated glomerular filtration rate (eGFR) was 61.78 ± 27.72 ml/min/1.73 m², with a mean serum creatinine of 126 ± 67.83 μmol/l at the time of kidney biopsy. Among the patients, 51.2% had an eGFR below 60 ml/min, indicating CKD stage 3 or worse according to the KDIGO classification Binary logistic regression analysis identifies anemia as a significant contributor to disease progression, with a risk influence approximately 3.3 times higher for GFR decline over time. Anemia emerges as a crucial predictor for serum creatinine doubling, carrying a higher risk than hyperuricemia. Analyses of C3 (p = 0.658), BAFF (p = 0.432), and APRIL (p = 0.227), demonstrated no significant differences in their serum levels between IgAN patients and healthy volunteers. Conclusion This study provides comprehensive insights into IgAN in the Bulgarian population, addressing the dearth of epidemiological data and biomarkers. Anemia emerges as a significant predictor for disease progression, emphasizing its potential clinical relevance. However, C3, BAFF, and APRIL exhibit no notable variations, underscoring the need for additional biomarker exploration to enhance understanding of IgAN dynamics in this population. Figure 1: Serum levels of C3 in IgAN patients and healthy controls. IgAN, immunoglobulin A nephropathy. Figure 2: Serum levels of BAFF in IgAN patients and healthy controls. BAFF, B-cell activating factor; IgAN, immunog