Predicting gastrointestinal and renal involvement in adult IgA vasculitis

Immunoglobulin A vasculitis (IgAV) is still poorly defined in the adult population. We aimed to determine the predictors of gastrointestinal (GI) or renal involvement in adult IgAV.

The prospective study included histologically proven adult IgAV cases diagnosed between January 2013 and July 2019 at our secondary/tertiary rheumatology center. We evaluated the role of clinical and the laboratory parameters as markers predicting the GI or renal involvement in IgAV, using the multiple logistic regression analysis.

During the 79-month observation period, we identified 214 new adult IgAV cases (59.3% males, median (interquartile range) age 64.6 (57.2-76.7) years). The GI tract and renal involvement developed in 58 (27.1%) and 83 (38.8%) cases, respectively (concurrently in 26 (12.1%) cases). In the multivariate logistic regression analysis, generalized purpura (OR 6.74 (95%CI 3.18-14.31)), the pre-treatment neutrophil to lymphocyte ratio (NLR) > 3.5 (OR 2.78 (95%CI 1.34-5.75)), and elevated serum IgA levels (OR 0.40 (95%CI 0.20-0.79)) were extracted as factors associated with GI complications, whereas current smoking (OR 3.23 (95%CI 1.50-6.98)), generalized purpura (OR 1.98 (95%CI 1.08-3.61)), elevated serum IgA (OR 2.25 (95%CI 1.21-4.18)), NLR > 3.5 (OR 1.96 (95%CI 1.02-3.77)), and marginally age (1.02 (95%CI 1.01-1.04)) emerged as factors associated with renal complications.

Generalized purpura and pre-treatment NLR predicted both GI and renal involvement, whereas active smoking was associated with renal involvement, and the serum IgA level had a divergent effect on renal and GI involvement in adult IgAV.