Role of proteinuria reduction in the progression of IgA nephropathy

Proteinuria has been shown to play a causal role in the progression towards ESRD of IgA nephropathy (IgAN). We demonstrated that steroids are effective in reducing proteinuria and preserving renal function.

to evaluate the long-term effect of steroids in IgAN patients (6th year evaluation) and better clarify the role of proteinuria reduction in slowing down the progression.

multicenter randomized controlled trial of 86 adult IgAN patients with serum creatinine < or = 1.5 mg/ dL and moderate proteinuria. They received either supportive therapy or methylprednisolone 1-g i.v. for three days at months 1, 3, and 5, plus oral prednisone (0.5 mg/kg every other day for six months).

Proteinuria significantly decreased in the treated patients (from 2.0+/-0.60 g/24 h at baseline to 1.0+/-0.68 g/24 h at six months) and remained stable till the 6th year (0.67+/-0.5 g/24 h), it slightly decreased in the control group. Six-year renal survival was significantly better in the steroid than in the control group: 9 patient (20.9%) in the steroid group and 15 (34.8%) in the control group reached the primary end-point of a 50% increase in serum creatinine from baseline. Five controls and none of the steroid-treated patients started dialysis. Steroid-treated patients did not experience any major side effects during follow-up.

Steroids significantly reduce proteinuria and protect against renal function deterioration in IgAN patients. Early reduction of proteinuria could also be marker of a persistent reduction in its levels over time and of a better outcome in the long term.