Clinicopathological characteristics and short-term follow-up outcomes of IgA vasculitis nephritis in pediatric and adult patients: a retrospective study

To compare the clinical manifestations, laboratory findings, renal pathological features, immune complex deposition patterns, and short-term follow-up outcomes between pediatric and adult patients with IgA vasculitis nephritis (IgAVN). A retrospective review of 441 biopsy-confirmed IgAVN patients was conducted. Patients were divided into pediatric (age < 18 years, n = 305) and adult (age ≥ 18 years, n = 136) groups. General demographic data, clinical classification, laboratory parameters, pathological grades (glomerular and tubulointerstitial), immune complex deposition patterns, and short-term follow-up outcomes were collected and compared between the two groups. Significant differences were found in sex distribution, time from IgAVN to kidney biopsy, and clinical classification. The adult group had higher levels of urea (BUN), creatinine (Cr), uric acid (UA), fibrinogen (FIB), IgG, IgA, C3, and C4, whereas the pediatric group had higher prothrombin time (PT), thrombin time (TT), D-dimer (DD), and fibrin degradation product (FDPs) levels. The degree of glomerular pathological injury and chronic tubulointerstitial injury were significantly more severe in the adult group than in the pediatric group, whereas no statistically significant difference was observed in the overall distribution of acute tubulointerstitial injury or immune complex deposition patterns. Prognosis was worse in the adult group. Adult patients showed a greater burden of chronic histopathological lesions and a less favorable distribution of short-term outcome categories than pediatric patients. These differences were associated with age group but may also reflect differences in biopsy timing, baseline kidney function, and treatment exposure. Not applicable.