Characteristics of hospitalized children with immunoglobulin A vasculitis: a 7-year retrospective study of 119,217 pediatric inpatients in China

Background Immunoglobulin A vasculitis (IgAV), formerly Henoch-Schonlein purpura (HSP), is the most common systemic vasculitis in children. This study aimed to systematically analyze the demographic, epidemiological, clinical, and infectious characteristics of pediatric IgAV using a large-scale real-world dataset. Methods A retrospective study was conducted using inpatient discharge abstracts from Beijing Children's Hospital, Capital Medical University, spanning January 2016 to December 2022. A total of 119,217 pediatric patients (aged 18 years or younger) diagnosed with IgAV were enrolled. Demographic characteristics, clinical classification, infectious triggers, pathogen spectrum, and multisystem comorbidities and complications were systematically analyzed. Statistical analyses were performed using SPSS 26.0. A two-sided P < 0.05 was considered statistically significant. Results Among 119,217 enrolled patients, the mean age was 7.79 ± 3.17 years with a male-to-female ratio of 1.30:1. School-aged children (50.77%) and Han ethnicity (93.27%) predominated. Southern China (57.91%) and rural areas (56.91%) showed higher case volumes (both P < 0.001). The winter-spring period (November-March) concentrated 50.66% of cases ( P < 0.001). Clinically, unspecified type was most common (57.02%), followed by renal type (20.04%). Renal-type cases showed a significant increasing trend ( P < 0.001). Co-infections were present in 47.49% of patients. Mycoplasma pneumoniae was the most frequently recorded pathogen (5.82%), compared with Streptococcus pneumoniae (0.32%). Digestive system complications were most prevalent (4.97%). Conclusions Pediatric IgAV in this large Chinese inpatient cohort demonstrated male predominance, a winter-spring peak, and an increasing proportion of renal-type classification (from 15.5% to 27.0% over 7 years). Mycoplasma pneumoniae was the most frequently recorded pathogen (5.82%). These findings suggest that systematic multi-pathogen screening (including Mycoplasma pneumoniae) and standardized long-term urinalysis follow-up may be warranted in the management of hospitalized pediatric IgAV patients.