Early post-treatment remission of proteinuria is associated with long-term prognosis in patients with immunoglobulin A nephropathy.

Abstract

Objective: To investigate the relationship between remission status and the optimal thresholds of proteinuria and hematuria after 6 months of treatment in patients with Immunoglobulin A Nephropathy (IgAN), and to assess their predictive value for long-term prognosis.

Methods: A retrospective analysis was conducted on 440 IgAN patients. Receiver Operating Characteristic (ROC) curves were employed to determine the optimal thresholds for proteinuria and hematuria remission at 6 months post-treatment initiation. Patients were stratified into four groups based on these thresholds and their remission status. Comparative analysis of baseline clinical characteristics was performed across groups. Kaplan-Meier survival analysis was utilized to assess differences in composite kidney outcomes, and multivariate Cox regression analyses were conducted to evaluate the relationship between remission patterns and these outcomes.

Results: The optimal thresholds for remission were identified as 0.80g/g for urinary protein and 13 RBC/μl for hematuria. Significant disparities in systolic blood pressure, diastolic blood pressure, body mass index, hemoglobin, serum creatinine, and estimated Glomerular Filtration Rate (eGFR) were observed among the four groups. During a median follow-up period of 33 months, 67 composite kidney events were recorded. Kaplan-Meier analysis revealed that patients achieving remission in both proteinuria and hematuria exhibited the highest survival rates, contrasting with the lowest rates in those with persistent proteinuria and hematuria (P < 0.001). Log-rank test analysis revealed no statistically significant differences in survival rates between the complete remission and proteinuria remission with persistent hematuria groups (P = 0.099), nor between the proteinuria persistence with hematuria remission and complete persistence groups (P = 0.513). Multivariate Cox analysis revealed that arteriolar hyalinosis is an independent risk factor for composite renal endpoint events in IgAN patients (HR, 2.687; 95%CI, 1.158-6.235; P = 0.021). Compared to the complete remission group, both the proteinuria persistence with hematuria remission group (HR, 8.649; 95%CI, 2.353-31.792; P = 0.001) and the complete persistence group (HR, 6.580; 95%CI, 1.936-22.360; P = 0.003) exhibited significantly higher risks of reaching endpoint events. Elevated baseline hemoglobin levels can reduce the risk of disease progression in IgAN patients (HR, 0.982; 95%CI, 0.967-0.996; P = 0.013).

Conclusion: Proteinuria remission is significantly associated with long-term prognosis in IgAN patients. Achieving proteinuria levels below 0.80 g/g after 6 months of initial treatment may indicate favorable control targets in IgAN management.