IgA Nephropathy: Mechanisms, Risk Stratification, and Precision Therapy

IgA nephropathy is the most common primary glomerulonephritis worldwide and a leading cause of chronic kidney disease and kidney failure, with geographic and ancestral variation and a course ranging from asymptomatic urinary abnormalities to progressive loss of kidney function. This narrative review links the multi-hit model to risk stratification, biomarkers, current management, and emerging therapies, and highlights implementation gaps. Risk assessment is longitudinal, prioritizing proteinuria and estimated glomerular filtration rate trajectories and integrating Oxford MEST-C, prediction tools, and biomarker and multi-omics approaches, while recognizing limitations in histologic reproducibility and model calibration. Current management is anchored in optimized supportive care aimed at sustained proteinuria reduction and kidney protection, including intensive blood pressure control with maximal tolerated renin–angiotensin system blockade, dietary sodium restriction and lifestyle measures, and sodium–glucose co-transporter 2 inhibitors for eligible patients. For selected higher-risk patients with persistent proteinuria despite optimized supportive care, immunomodulatory strategies are discussed, including systemic corticosteroids and targeted-release budesonide (Nefecon), emphasizing structured toxicity risk mitigation and cautioning against assuming interchangeability among alternative oral budesonide formulations. Emerging therapies are organized around mechanism-aligned targets across the BAFF/APRIL axis, complement pathways, and endothelin-based approaches, with growing interest in sequencing and combination regimens layered on supportive care. Key gaps include reliance on surrogate endpoints, limited long-term durability and safety data, and uneven evidence for special populations.