Establishment and validation of a novel risk stratification scale in adult IgA vasculitis nephritis: a cohort study based on a systematic review and meta-analysis

OBJECTIVES: This study aimed to develop and validate a risk stratification scale for unfavourable outcomes in adult patients with IgA vasculitis nephritis (IgAVN). METHODS: The derivation cohort in this study was constructed using the existing prognosis data from adult IgAVN cohorts. We extracted the risk factors and their hazard ratios. Only statistically significant risk factors were included in our final risk stratification scale. Then this study validated the risk stratification scale in an external cohort of Chinese patients. The performance of the risk stratification scale was evaluated by the receiver operating characteristic (ROC), calibration, decision, and Kaplan-Meier curves. RESULTS: Ten cohorts involving 1,814 adult patients with IgAVN were included in this meta-analysis. Serum albumin (ALB), estimated glomerular filtration rate (eGFR), endocapillary hypercellularity (E1), and tubular atrophy/interstitial fibrosis (T1/2) were included in the risk stratification and scored according to their weightings (maximum score: 6.5). An external cohort comprising 133 patients was used to validate the risk stratification scale. The area under the curve (AUC) value of the scoring scale was 0.88 (95%CI: 0.78-0.99), with a sensitivity of 0.79 (95%CI: 0.49-0.95) and specificity of 0.89 (95%CI: 0.82-0.94), at a cut-off value of 3. The calibration, decision, and Kaplan-Meier curves further confirmed the robust performance of the risk stratification scale. CONCLUSIONS: In this study, we established a simple and practical tool to identify adult IgAVN patients at high risk of unfavourable outcomes. Reasonable use of the risk stratification scale can help make early clinical decisions and facilitate the development of precision medicine.