Age of onset as a risk factor of renal involvement in Henoch-Schönlein purpura

BACKGROUND Henoch-Schönlein purpura (HSP) is the most common vasculitis in children, characterized by triad of symptoms; palpable purpura without thrombocytopenia, abdominal pain, and arthritis. Renal involvement often occur in children with HSP. No data on the renal involvement of children with HSP in Indonesia, especially West Java. OBJECTIVE To evaluate renal involvement in children with HSP. METHODS Retrospective study was conducted in children with HSP in Department of Child Health, Hasan Sadikin Hospital, from 2006 to 2011. Characteristics and clinical manifestations was reviewed from medical record. HSP was diagnosed by American College of Rheumatology 1990 criteria or European League Against Rheumatism/Pediatric Rheumatology International Trials Organization/Pediatric Rheumatology European Society 2008. RESULTS There were 128 patients, consisting of 82 male (64.9%) and 46 female (35.1%) with ratio 1.8:1. Mean age was 7.9 ± 2.9 years old which range from 6 month to 15 years. Peak morbidity was between 5-10 years old. Prevalence of HSP in Hasan Sadikin Hospital tend to raise from 2.7/100,000 in 2008 to 5.2/100,000 in 2010. In most patients (71%) purpura was the first symptom. Seventy-one patients (44.5%) had arthritis and 89 patients (69.5%) had abdominal pain, while renal involvement was in 28 patients (21.8%). Gastrointestinal manifestations tend to manifest in patients less than 5 years old (p = 0.267), while renal involvement tend to manifest in age group 11-15 years old (p = 0.015) with odds ratio 3.1 (95% confidence interval, 1.2-8.1). CONCLUSION Renal involvement in children with HSP is more common in age group 11 to 15 years old.