Diagnostic value of hematological inflammatory indices for renal involvement in adult IgA vasculitis

This study aimed to evaluate the diagnostic value of hematological inflammatory indices, including neutrophil-to-lymphocyte ratio (NLR), red cell distribution width (RDW), and aggregate index of systemic inflammation (AISI), for detecting renal involvement in adult patients with immunoglobulin A (IgA) vasculitis. A cross-sectional study was conducted in 67 adult patients with IgA vasculitis (IgAV) and 70 healthy controls at 103 Military Hospital, Vietnam. Compared with healthy controls, patients with IgAV showed higher white blood cell, neutrophil, and monocyte counts, as well as elevated NLR and AISI, and lower hemoglobin levels (all P < .05). Renal involvement was identified in 38.8% of patients. Those with renal involvement had significantly higher RDW, NLR, and AISI than patients without renal involvement. Receiver operating characteristic analysis showed moderate diagnostic performance, with area under the curves (AUCs) of 0.682 for NLR, 0.675 for RDW, and 0.674 for AISI. The combined RDW + NLR model improved diagnostic accuracy (AUC = 0.759, 95% CI: 0.636–0.882), while the RDW + AISI model showed the best performance (AUC = 0.797, 95% CI: 0.684–0.911), with sensitivity of 53.8% and specificity of 95.1% ( P < .001). Univariate analysis showed that elevated RDW, NLR, and AISI were significantly associated with renal involvement. Multivariate logistic regression adjusted for age and sex confirmed these indices as independent predictors. RDW, NLR, and AISI are independently associated with renal involvement in adult IgAV. The combination of RDW and AISI demonstrated the highest diagnostic performance and may serve as a simple, cost-effective tool for identifying patients at increased risk of renal involvement.