Clinical Significance of Increased Degree of Hematuria in Patients affected by IgA Nephropathy.

BACKGROUND: The clinical significance of increased degree of hematuria in patients affected by primary IgA Nephropathy (IgAN) remains unclear, highlighting the need for further investigation. METHODS: From January 2018 to December 2024, a total of 696 IgAN patients with persistent hematuria were enrolled to conduct a retrospective single-center study. Patients with a follow-up-to-baseline time-averaged hematuria ratio (Δ u-RBC count) ≥1 were assigned to the Increased-hematuria group. The remaining patients were 1:1 matched by age, gender, baseline estimated glomerular filtration rate (eGFR), and follow-up duration to form the Decreased-hematuria group. Survival was analyzed via the Kaplan-Meier (K-M) method and generalized linear mixed-effects model (GLMM), and risk factors for survival were identified using the Cox proportional hazards model. RESULTS: The Increased-hematuria and Decreased-hematuria groups each included 219 patients, with no significant difference in time-averaged hematuria degree between groups. Despite matched baseline demographic data and renal function, both K-M analysis (P = 0.03) and GLMM (P < 0.01) demonstrated that the Increased-hematuria group had significantly poorer prognosis than the Decreased-hematuria group. Increased hematuria degree was identified as an independent risk factor for reaching the composite endpoint (sustained ≥ 30% decline in eGFR from baseline or progression to end-stage renal disease [ESRD]). Notably, more substantial reduction in proteinuria levels was presented in Decreased-hematuria group but is not directly associated with prognosis among these patients. CONCLUSIONS: Increased hematuria degree is associated with adverse outcomes in patients affected by IgAN, underscoring its potential as a prognostic indicator.