The effectiveness of steroid therapy for patients with advanced IgA nephropathy and impaired renal function.

BACKGROUND: Recent studies have shown that steroid therapy is effective for IgA nephropathy (IgAN) in patients with moderate proteinuria and active histological findings. However, the effectiveness of steroid therapy has not been determined yet in patients with advanced IgAN and impaired renal function.

METHODS: Sixty IgAN patients whose creatinine clearance was under 70 ml/min at the time of renal biopsy were studied retrospectively. The patients were divided into two groups according to treatment: a steroid group ( n = 20) and a nonsteroid group ( n = 40). The mean age was 39.6 +/- 14.9 years in the steroid group and 40.6 +/- 10.9 years in the nonsteroid group. The mean follow-up period was 4.5 +/- 2.2 years in the steroid group and 4.6 +/- 2.4 years in the nonsteroid group. Patients with high proteinuria and high histological activity were treated with prednisolone. Clinical and histological findings before treatment and the outcome after treatment were analyzed.

RESULTS: In the retrospective analysis, the amount of urinary protein excretion before treatment tended to be higher in the steroid group than in the nonsteroid group, but was not significantly different (2.33 +/- 1.54 vs 1.39 +/- 1.87 g/day). Histologically, the percentage of patients with crescent formation, especially that of cellular or fibrocellular crescents, was significantly higher in the steroid group than in the nonsteroid group (17.2 +/- 15.9% vs 2.3 +/- 4.5%; P < 0.0001). The grades of mesangial cell proliferation (1.65 +/- 0.55 vs 1.21 +/- 0.47; P = 0.002) and mesangial matrix increase (1.88 +/- 0.64 and 1.41 +/- 0.67; P = 0.01) were higher in the steroid group than in the nonsteroid group. In the evaluation of the outcome after treatment, the amount of urinary protein excretion at 1 year after treatment had significantly decreased in the steroid group (before treatment, 2.33 +/- 1.54 g/day; at 1 year, 1.02 +/- 0.98 g/day; P = 0.003), but the amount remained unchanged in the nonsteroid group (before treatment, 1.39 +/- 1.87 g/day; at 1 year, 1.28 +/- 2.19 g/day). The levels of serum creatinine before treatment and at 1 year after treatment were not changed in either of the groups, however, in the nonsteroid group, the level at the final observation was significantly higher than the level before treatment (2.51 +/- 3.43 vs 1.27 +/- 0.33 mg/dl; P = 0.0219).

CONCLUSIONS: In the present study, in advanced IgAN patients whose creatinine clearance was under 70 ml/min, steroid therapy effectively reduced the amount of proteinuria and maintained the serum creatinine level, if the treatment was selectively applied to patients with a moderate amount of proteinuria and active glomerular lesions such as cellular and fibrocellular crescents, and mesangial cell proliferation.