Clinical characteristics and risk factors for kidney involvement in children with immunoglobulin A vasculitis.

Background: Immumoglobulin A (IgA) vasculitis (IgAV), formerly known as Henoch-Schönlein purpura (HSP), is a self-limiting systemic vasculitis in children. Kidney involvement is associated with a long-term unfavorable outcome and can lead to significant morbidity. This study was conducted to describe the clinical and laboratory characteristics of childhood IgAV with kidney involvement and to identify risk factors associated with IgAV nephritis (IgAVN).

Methods: This was an ambidirectional descriptive study of 77 children with IgAV. All demographic data, clinical features, and laboratory tests were collected from electronic medical records from January 2010 to December 2022. Risk factors for kidney involvement in IgAV were assessed using multivariate logistic regression. Kaplan-Meier survival analysis was used to calculate the time to commencement of kidney involvement.

Results: Twenty-five children (32.4% of the IgAV patients) developed IgAVN. The common findings in IgAV with kidney involvement were microscopic hematuria (100%), nephrotic range proteinuria (44%), and non-nephrotic range proteinuria (40%). Multivariate logistic regression showed that age greater than 10 years (adjusted hazard ratio, AHR 4.66; 95% confidence interval, CI, 1.91-11.41; p = 0.001), obesity (body mass index, BMI, z-score ≥ +2 standard deviations, SDs) (AHR 3.59; 95% CI 1.41-9.17; p = 0.007), and hypertension at onset (AHR 4.78; 95% CI 1.76-12.95; p = 0.002) were associated significantly with kidney involvement. During follow up, most IgAV patients developed nephritis within the first 9 months.

Conclusion: Age greater than 10 years, obesity, and hypertension at presentation were predictive factors for IgAVN. Our study emphasized that IgAV patients with risk factors should be closely monitored for at least 1 year after the onset of the disease.