Background: The natural course of idiopathic membranous nephropathy (IMN) is variable and the role of immunosuppressive therapy is controversial. In our centre, the strategy has been conservative: the immunomodulating treatment (glucocorticoids and/or cyclosporine A) has been targeted to patients at high risk of developing progressive renal disease and the cytotoxic drugs have been used cautiously. The aim of this retrospective observational study was to evaluate the efficacy of this strategy.
Methods: We evaluated the clinical course and outcome of IMN patients diagnosed between 1993 and 2003. Risk assessment was done during an observation period of ≥6 months after the initial renal biopsy. Patients were followed up until death, the development of end-stage renal disease (ESRD) or the last clinical visit (before December 2006). Treatments and their side effects were recorded.
Results: One hundred and forty-two patients with membranous nephropathy were diagnosed of which 81 were idiopathic. The clinical course of 76 IMN patients (38 high risk and 38 low risk) were followed up [mean duration 66 ± 40 (median 59) months]. Thirty-five patients were treated with immunosuppressive drugs, and at last follow-up, 71% of them were in complete or partial remission. The overall response rate of this therapy was 83%. 11% of the high-risk patients had reached ESRD. For the high-risk patients, 10-year survival (alive with glomerular filtration rate >10 mL/min/1.73 m(2)) was 79%. No major side effects were observed.
Conclusions: This study suggests that targeted, stepwise, cytotoxic drug-sparing immunosuppressive treatment in IMN was associated with favourable renal, as well as overall survival among patient at risk of developing ESRD.