External validation of the pediatric International IgA Nephropathy Prediction Tool in a central China cohort.

BACKGROUND: This study aimed to externally validate the pediatric International IgA Nephropathy (IgAN) Prediction Tool updated from the adult IgAN Prediction Tool. METHODS: 439 children with biopsy-confirmed idiopathic IgAN were enrolled in this external validation study. The primary outcome was a 30% decline in eGFR or end-stage kidney disease. We evaluated the discrimination using Harrell's C-index, the receiver operating characteristic (ROC) curve, and Kaplan-Meier curves for four risk groups (< 16th [low risk], ∼16 to < 50th [intermediate risk], ∼50 to < 84th [high risk], and ≥ 84th percentiles [highest risk] of linear predictor). Calibration was assessed using calibration plots. RESULTS: The median follow-up time of the 439 patients was 4.5 (2.7-6.8) years, and 27 patients reached the primary outcome. Compared with the reported cohorts, our cohort was more contemporary, with milder proteinuria at biopsy, and had lower proportions of S1 and T1 lesions. Harrell's C-index and area under the ROC curve at 5 years were < 0.7 for both the models with and without race. The Kaplan-Meier curves of the risk groups were not well separated for the two models, only separated completely between the highest-risk group and the others for the model without race. The two models generally overestimated the risk of the primary outcome, CONCLUSION: The model without race could accurately distinguish the highest-risk patients from patients with low, intermediate, and high risk for kidney progression. Discrimination and calibration for the full model with or without race were unsatisfactory in this contemporary cohort in central China.

The association between dental caries and steroid-sensitive nephrotic syndrome in children.

BACKGROUND: Pathogenesis and relapse of steroid-sensitive nephrotic syndrome (SSNS) are primarily associated with infection. Dental caries is the most common chronic progressive oral infection in children. However, clinical studies of SSNS combined with dental caries in children are rare. METHODS: In our retrospective cohort study from January 2021 to June 2022, 145 children with SSNS were included in the baseline analysis and 105 in the follow-up analysis. The follow-up period was 1 year. The primary study endpoints were the relapse-free period and frequently relapsing nephrotic syndrome (FRNS). Secondary endpoints included the number and triggers of relapses and concomitant medications. RESULTS: The median age was 5.5 years, with a caries rate of 60.7%, the mean DMFT/dmft was 3.86, and the caries filling rate was 1.6%. Except for the lower proportion of high household income and high parental education observed in the caries group, no statistical differences were found when comparing the other baseline data with the non-caries group. The caries group had a shorter relapse-free period and a lower 1-year cumulative relapse-free survival rate (HR = 1.90, 95% CI 1.17-3.09, P = 0.009). Univariate regression analysis showed caries associated with FRNS (OR = 2.714, 95% CI 1.021-7.219, P = 0.045), but the correlation no longer remained in the multivariate analysis. Additionally, seven cases of caries-derived pulpal periapical inflammation triggered SSNS relapses. The caries group had more infection triggers and concomitant medication use. CONCLUSION: Dental caries and relapse of SSNS are potentially associated, but careful evaluation is needed.