Risk factors for persistent proteinuria after a 2-year combination therapy for severe childhood IgA nephropathy.

BACKGROUND: Although a 2-year combination therapy is effective for severe childhood immunoglobulin A (IgA) nephropathy, proteinuria persists in some patients even after the treatment.

METHODS: Seventy-nine patients aged <18 years with IgA nephropathy in which >80 % of glomeruli showed mesangial proliferation were enrolled in the study. Risk factors for persistent proteinuria after combination therapy were investigated using multivariate logistic regression analysis.

RESULTS: Proteinuria (≥0.2 g/1.73 m(2)/day) persisted in 27 patients (34 %) after the combination therapy. Twenty-four-hour urinary protein excretion, rate of glomeruli with crescents, rate of glomeruli with segmental sclerosis and rate of glomeruli with global sclerosis at diagnosis were higher in patients with persistent proteinuria than those without. In the multivariate analysis, 24-h urinary protein excretion [odds ratio (OR) 6.9; 95 % confidence interval (CI) 2.1-27.8; p = 0.001] and rate of glomeruli with crescents (OR 3.8; 95 % CI 1.1-13.9; p = 0.03) were independent risk factors for persistent proteinuria. Analysis of the receiver operating characteristic curve demonstrated that the most accurate cut-off values to detect persistent proteinuria were a urinary protein excretion of 1.32 g/1.73 m(2)/day and a 14 % rate of glomeruli with crescents.

CONCLUSIONS: In our cohort, urinary protein excretion and rate of glomeruli with crescents at diagnosis were independent risk factors for persistent proteinuria after the combination therapy.