Clinical Characteristics of Biopsy-Proven IgA Vasculitis in Children and Adults: A Retrospective Cohort Study

Objective: To describe the differences in clinical characteristics and outcome between adult- and childhood-onset biopsy-proven IgA vasculitis (IgAV) in North America. Patients and Methods: Patients with IgAV diagnosed from January 1, 1997, through December 31, 2016, were retrospectively identified. Data were abstracted from direct medical record review. Kaplan-Meier methods were used to estimate survival rates. Results: A total of 243 patients with IgAV were included (227 [93.4%] white, 141 [58.0%] male); 174 patients were adults (≥21 years), and 69 were younger than 21 years. Compared with patients younger than 21 years, adults at baseline more frequently had ulcerative skin lesions (19 [10.9%] vs 1 [1.4%]; P=.02) and nephrotic-range proteinuria (21 of 96 [21.9%] vs 1 of 38 [2.6%]; P=.007) but less commonly had abdominal pain (59 [33.9%] vs 42 [60.9%]; P<.001), ischemic gastrointestinal tract involvement (18 [10.3%] vs 14 [20.3%]; P=.04), and arthralgias (66 [37.9%] vs 42 [60.8%]; P<.001). During 389 person-years of follow-up, 29 deaths were observed. Five-year survival rates for patients aged younger than 21, 21 to 50, and 51 years or older were 100%, 94%, and 40%, respectively. In comparison to data from the United States life tables for whites, patients 51 years or older at diagnosis had a greater than 7-fold increased risk of mortality (standardized mortality, 7.60 [95% CI, 5.01-11.06]; P<.001). Conclusion: IgA vasculitis in adults is associated with more severe skin/kidney involvement and poorer renal outcome. Among adults with IgAV, patients aged 51 years or older at diagnosis have significantly higher mortality (P<.001).