A Cochrane review included 13 studies with a total of 1 403 subjects. Eight studies examined the efficacy of therapies to prevent persistent kidney disease in Henoch-Schönlein purpura (HSP) and 5 examined therapies to treat established severe kidney disease. Twelve studies included children and 1 study investigating treatment for severe kidney disease included adults.
Preventing persistent kidney disease: In children given prednisone for 14 to 28 days at presentation of HSP compared with placebo or supportive treatment, there was no significant difference in the risk of persistent kidney disease any time after treatment (RR 0.74, 95% CI 0.42 to 1.32; 5 studies, n=746). There were no significant differences in the risk of persistent kidney disease with antiplatelet therapy in children with or without kidney disease at entry. Intravenous heparin significantly reduced the risk of persistent kidney disease at 3 months or longer after the onset or relapse of HSP compared to placebo (RR 0.27, 95% CI 0.14 to 0.55; 1 study, n=228); no significant bleeding occurred.
Treating severe kidney disease: In children with severe HSP-associated kidney disease, there was no significant difference in the risk of persistent kidney disease with cyclophosphamide compared with placebo or supportive treatment (2 studies, n=110). Adverse effects of cyclophosphamide were not reported. In one study comparing cyclosporin with methylprednisolone (n=15) there was no significant difference in remission at final follow-up at a mean of 6.3 years (RR 1.37, 95% CI 0.74 to 2.54). In one study (n=17) comparing mycophenolate mofetil with azathioprine, there was no significant difference in the remission of proteinuria at one year (RR 1.32, 95% CI 0.86 to 2.03). No studies were identified which evaluated the efficacy of therapy on kidney disease in participants with recurrent episodes of HSP.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and lack of blinding), and by imprecise results (wide confidence intervals).