The average time from the diagnosis of HSP to endothelial function evaluation was 6 ± 3.5 years (median- 6 years). The average RHI value in the patients with HSP was similar to the control group (1.8 ± 0.7 vs 1.87 ± 0.35 p = 0.18). Twelve of 19 (63%) of the children with HSP had abnormal RHI compared with 7/23 (30%) in the control group (p = 0.06).