Henoch-Schönlein Purpura

Risk Factors for the Development of Nephritis in Henoch-Schönlein Purpura

Shin JI, Park JM, Shin YH, et al.

Henoch-Schönlein purpura (HSP) is one of the most common vasculitides in childhood. In addition to palpable purpura, patients often have abdominal pain, arthritis, and renal disease, including nephritis, proteinuria, nephrotic syndrome, and hypertension. Most will recover without sequelae, but up to 7% can develop end stage renal disease (ESRD). Few studies have analyzed risk factors for developing nephritis, relapse, or proteinuria
The authors from South Korea carried out a retrospective study of 206 children with HSP (age at onset 7.2 ± 2.8 years, duration of follow-up 3.1 ± 2.2 years) who were seen at Yonsei University, Seoul from 1996 to 2001, to identify factors associated with developing nephritis, relapse, or proteinuria. They excluded patients with <1>20mg/m2/hr, relapse as flare of disease following an asymptomatic period of 1 month or more, and nephritis as hematuria (>5 red blood cells per high-power field in a centrifuged specimen) with or without proteinuria.
In univariate analyses, age >10 years, persistent purpura, severe bowel angina, and relapse were associated with developing nephritis. Arthritis was less common in those developing nephritis. Age >10 years, persistent purpura, relapse, and severe bowel angina were associated with significant proteinuria. In the multivariate analysis, only age >10 years, persistent purpura, and relapse remained associated with an increased risk of developing nephritis, while relapse and severe bowel angina were associated with significant proteinuria. Multivariate analysis showed that age >10 years, persistent purpura, and severe bowel angina were associated with relapse. The authors demonstrated a predictive model for developing nephritis or significant proteinuria based on those variables that had a P<.05 on univariate analysis (age >10 years, persistent purpura, severe bowel angina, and relapse). When applied to their patients’ data, the risk effect from these factors was additive (as suggested by the multivariate analysis). The greater the number of factors present, the higher the risk for developing nephritis or significant proteinuria. For example, children with no risk factors for nephritis developed nephritis 20% of the time; with 1 risk factor, it was approximately 45%; with 2 risk factors, about 65%; 3 risk factors carried a nephritis risk of 80%; and those with 4 risk factors all developed nephritis (total of only 5 patients in this group).

Scand J Rheumatol. 2006;35:56–60;