Predictors of Gastrointestinal Involvement in Children with IgA Vasculitis: Results from a Single-Center Cohort Observational Study

Background and objective: IgA vasculitis (IgAV), a predominantly pediatric leukocytoclastic disease, has an unpredictable, though largely benign, evolution. The aim of this study was to retrospectively investigate any potential clinical or laboratory predictors of gastrointestinal involvement in a single-center cohort of children with IgAV. Patients and methods: A total of 195 children with a history of IgAV, regularly followed-up for an average period of 1 +/- 2.6 years via outpatients clinics of the pediatric rheumatology unit in our University, were assessed, analyzing their clinical and laboratory variables in relationship with their disease evolution and outcome. Results: Univariate analysis showed that a higher neutrophil granulocyte count and lower lymphocyte count (expressed as a percentage of the total white blood cells) were significantly associated with the presence of gastrointestinal involvement at the first examination (65.2 +/- 13% versus 58.8 +/- 12%, p = 0.02, and 26.4 +/- 11% versus 32.1 +/- 11%, p = 0.02, respectively). A positive pharyngeal swab for Streptococcus pyogenes, a deficiency of 25-hydroxyvitamin D, a persistence of purpuric rash for more than 1 month, and purpuric lesions in the genital area were also associated with gastrointestinal involvement (p = 0.0001, p = 0.0001, p = 0.007 and p = 0.001, respectively). However, multiple logistic regressions with correction for the patients' sex and age showed that lower 25-hydroxyvitamin D levels, persistent rash, and genital lesions were independently and significantly associated with signs of gastrointestinal involvement. We then performed a secondary analysis (both univariate and multivariate) to investigate whether vitamin D deficiency was associated with other IgAV manifestations: we found that only 25-hydroxyvitamin D deficiency remained significantly associated with gastrointestinal involvement in IgAV. Conclusions: Patients with IgAV and vitamin D deficiency might be more prone to developing gastrointestinal manifestations of variable severity.