Analysis on clinicopathology and prognosis of primary IgA nephropathy in children with massive proteinuria / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the clinicopathological features and the prognosis of IgA nephropathy (IgAN) in children with massive proteinuria.Methods:It was a retrospective cohort study. Clinical data of IgAN children with massive proteinuria admitted to the Department of Nephrology, Children's Hospital Affiliated to Capital Institute of Pediatrics from January 2008 to December 2021 were retrospectively analyzed. Patients were divided into effective group and ineffective group according to whether urine protein turned negative after 6 months of initial treatment. The follow-up endpoint event was defined as a reduction in proteinuria of less than 50% or end-stage renal disease (ESRD) achievement. MedCalc software was used to perform Kaplan-Meier survival analysis, and Log-rank test was used to compare the difference of renal survival between the two groups.Results:A total of 127 patients were diagnosed as primary IgAN by renal biopsy, of whom 57 patients with IgAN showed massive proteinuria. These 57 IgAN patients with macroproteinuria accounted for 44.9% of the total IgAN patients and were enrolled in the study. Among the 57 cases, 33 cases (57.9%) were Lee's grade Ⅲ, 11 cases (19.3%) were below Lee's grade Ⅲ, and 13 cases (22.8%) were above Lee's grade Ⅲ. The follow-up time was 4.0 (3.0,5.8) years. In the initial treatment, among 57 patients, 46 (80.7%) were effective (effective group) and 11 (19.3%) were ineffective (ineffective group). Compared with the effective group, the ineffective group had a higher proportion of concurrent AKI at the onset of disease and longer recovery time of renal function, with significant difference (7/11 vs. 13/46, χ2=4.878, P=0.027). Compared with the effective group, the proportion of Lee grade Ⅲ or above was higher in the ineffective group, and the difference was statistically significant (5/11 vs. 8/46, χ2=3.971, P=0.046). There were significant differences in endocapillary hypercellularity (E1), segmental glomerulosclerosis or adhesion (S1) and cellular/fibrocellular crescents (C2) of Oxford classification between IgAN children with Lee grade Ⅲ or below and those over Lee grade Ⅲ (11/13 vs. 20/44, χ2=6.204, P=0.013; 12/13 vs. 17/44, χ2=11.566, P=0.001; 9/13 vs. 7/44, χ2=14.131, P=0.001). Among 57 patients, endpoint events occurred in 2 patients who both were urinary protein unmitigated, and none of the children progressed to ESRD. There was no significant difference in cumulative renal survival between the two groups by Kaplan-Meier survival analysis and Log-rank test ( χ2=0.537, P=0.460) after addition of calcineurin inhibitors (CNIs) to the initial treatment ineffective group. Conclusions:Macroproteinuria is the prominent manifestation of IgAN in children. The pathological type is mainly Lee grade Ⅲ. Children with macroproteinuria have a good prognosis in the short and medium term after active treatment. For IgAN with macroproteinuria that does not respond well to initial treatment, AKI is more common at onset, and renal function recovery time is longer. The application of CNIs may have a certain effect on improving the renal outcome of IgAN with massive proteinuria.