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

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.