Background: Progressive deterioration in renal function occurs in 20-50% of patients with idiopathic membranous nephropathy (IMN). Several treatment regimens have been used to reverse this with varying effect and toxicity.
Methods: Thirteen patients (10 males, 3 females, median age 56 years) with IMN and progressive renal failure were treated with oral prednisolone 20-60 mg/day and azathioprine 1.3-2.7 mg/kgBW/day. All patients were followed up for a minimum of 2 years with a median follow-up of 73 months (range 24-103 months).
Results: Ten patients responded to treatment with a fall in serum creatinine and renal function stabilized in the remainder. Two patients relapsed, one of whom responded to an increase in immunosuppression, the other is now on dialysis. Proteinuria has significantly reduced in 10 patients, and only four patients still have nephrotic-range proteinuria. Mean (+/- SE) peak pretreatment serum creatinine of 229 (+/- 161) mumol/l and urinary protein of 11.8 (+/- 1.8) g/24 have fallen to 163 (+/- 65) mumol/l and 3.25 (+/- 1.0) g/24 h after 12 months treatment (P < 0.005, Wilcoxon matched pairs test). Immunosuppressive treatment has been successfully withdrawn in four patients after intervals ranging from 12 to 60 months. Adverse effects, which occurred in 10 patients, have been mild and have not led to treatment withdrawal though dose reductions have been necessary in some patients.
Conclusions: Oral prednisolone and low-dose azathioprine is an effective therapy for progressing renal failure due to IMN, and induces remission of nephrotic syndrome. Side-effects are less than other immunosuppressive regimens.