Introduction of a cyclophosphamide-based treatment strategy and the risk of ESRD in patients with idiopathic membranous nephropathy: a nationwide survey in the Netherlands

Abstract

Background: The efficacy of immunosuppressive therapy in preventing ESRD in patients with idiopathic membranous nephropathy (iMN) is debated. From 1991 onwards, we have advocated a restrictive treatment strategy in our university hospital and regional referring hospitals. We advised the use of immunosuppressive therapy, consisting of a combination of steroids and oral cyclophosphamide for 12 months, in patients with iMN at high risk for ESRD.

Methods: Primary renal diagnosis of all patients who start renal replacement therapy in the Netherlands is registered in the RENINE database. We studied the incidence of ESRD due to iMN in the Netherlands in the period 1991-2005. We mailed a questionnaire to all nephrology centres that entered a patient with ESRD and iMN in the RENINE database after 2000.

Results: The introduction of the cyclophosphamide-based treatment strategy in the Nijmegen region resulted in a significant 70% reduction in the incidence of ESRD in patients with iMN as compared to an unchanged incidence in other parts of the Netherlands. The response rate to the questionnaire was 65%. There were 45 patients (34 M, 11 F) with a mean age of 49 +/- 17 years at diagnosis and a median serum creatinine of 138 micromol/l (range 60-1798). Overall, only 22 patients (49%) had been treated with immunosuppressive therapy, consisting of prednisone monotherapy in 7.

Conclusions: Our data suggest that the introduction of a cyclophosphamide-based restrictive treatment policy has reduced the risk of ESRD in iMN. The questionnaires reflect the differences in opinion on the optimal treatment of high-risk patients with iMN.