- Clinical Findings
Clinical findings were shown in Table 1.The 1243 children had initial eGFR of 102±20 ml/min/1.73m2. The cohort was 32% female and all were Chinese Han children. The initial UP was 1.0 (0.5–2.4) g/d. Patients were followed for a median of 86.8(54.7–140.2) months, during which 45% received CS and 70% received RASB. MAP was 89±16mmHg, 14% experienced a combined event(ESRD or 50% reduction in initial eGFR) , and 6.6% experienced ESRD. During the follow-up, 70% of patients were treated with RASB and 45% with corticosteroids and19% were treated with corticosteroids combined other immunosuppressive drugs.
- Pathological Findings
Pathological findings were shown in Table 2.According to Oxford classification,29% of the children showed M1,35% showed E1, 37% showed S1, 23% showed T1,4.3% showed T2,44 % showed C1 and 4.6% showed C2. The distribution of the percentage of crescents observed in every children was shown in Figure 1. 28% had crescents in<10% of glomeruli, 9.4% had a fraction of glomeruli with crescents one tenth or more, whereas 6.6% had a fraction of glomeruli with crescents one sixth
or more, and only 4.6% had a fraction of glomeruli with crescents one fourth or more.The percentage of immunoglobulins deposited only in the mesangial region was 68%, while 32% of immunoglobulins were deposited in both the mesangial and capillary loop regions. 25% Children showed positive glomerular staining for IgG, 44% showed positive glomerular staining for IgM,84% Children showed positive glomerular staining for C3, and 1.1% Children showed positive glomerular staining for C4.The immunofluorescence intensity of IgA was between ++ and ++++, including 5.6% of ++, 13% of +++ and 81% of ++++.
- Effects of Different Kidney Biopsy Time on the Variables in Oxford Classification
We selected the median time(12 months) of onset to renal biopsy as the cut-off point to analyze the effect of biopsy time on variables in the Oxford classification. From Table3 ,we can see that when the median time of onset to renal biopsy was less than the median time, the patient's lesions were milder, dominated by S0(c2=354.5,P<0.001), T0 (c2=323.3,P<0.001), and C0(c2=437.6,P<0.001). On the contrary, when the time of renal biopsy was longer than the median time, the lesions were corrected mainly byS1,T1-2 and C1-2. With regard to E and M lesions, there was no significant difference in time from onset to renal biosy within available data.
- Relationship between Oxford Classification and Clinical Indicators
In order to study the correlation between Oxford classification and clinical indicators, three clinical indicators of MAP, eGFR, UP, which are closely related to renal prognosis, were selected for preliminary simple linear regression analysis. Correlations between pathological variables and clinical presentation at biopsy were shown in Table 4.M1,E1,T1-2 and C1-2 were associated with MAP at biopsy. S1,T1-2 and C1-2 were associated with eGFR at biopsy. All pathological variables were associated with UP at biopsy.
- Renal Survival In Patients With IgAN According To The Oxford Classification
As shown in Figure2, Kaplan-Meier revealed that S (log-rank,χ2=14.796,P<0.001,Figure2C),T (χ2=48.976, P<0.001,Figure2D), were associated with renal survival. M[χ2=1.459, P=0.477,Figure2A ], E (χ2= 2.399, P=0.121,Figure2B) and C(χ2=6.218, P=0.054,Figure2E ) were not associated with renal outcome.
- Cox Regression Analysis Of Oxford Classification Associated With Renal Outcomes
The Cox regression analysis results are shown in Table 5.Univariate Cox regression analysis also revealed that M[hazard ratio(HR)2.2,95% confidence interval(CI):1.5~3.3,P<0.001],S(HR3.1,95%CI,2.0~4.7,P<0.001),T(HR7.9, 95%CI,4.7~13.4,P<0.001) and C (HR3.4,95%CI,1.8~6.2,P<0.001) were associated with renal outcome. In multivariate Cox analysis,after adjustment by Cox regression model, S(HR2.7,95%CI,1.8~4.2,P<0.001) and T(HR6.6,95%CI,3.9~11.3,P<0.001)remained as independent predictors of renal outcome at the time of biopsy.
- Predictive value of M,E and C lesions between immunosuppressive and without immunosuppressive groups
We further assessed the predictive value of lesions (M,E and C)in patients without immunosuppression to assess their natural predictive value.Individuals with C lesions without immunosuppression experienced a worse survival from a combined event(Figure 3E), but this difference disappeared after the use of any immunosuppressants(Figure 3F).The predictive value of M and E lesions was not changed by adding immunosuppressants(Figure 3A-D).