Predictive factors of response to steroids and cyclophosphamide therapy in idiopathic membranous nephropathy

Objectives To investigate demographic and clinical factors which could be predictive of clinical remission or relapse in patients with idiopathic membranous nephropathy treated with oral steroids and iv cyclophosphamide therapy. Methods This was a retrospective cohort study where a total of 83 patients with biopsy-proven IMN who had received oral prednisone and iv cyclophosphamide for at least 6 months were enrolled. Demographic and clinical factors of these patients were analyzed at baseline and three months after the initiation of therapy to evaluate their respective effects upon clinical remission and relapse. Results Median follow-up duration was 20 (12-30) months. At the end of follow-up, 80.7% (67/83) of the patients attained remission and 47.0% (39/83) attained complete remission (CR). The amount of proteinuria at baseline and the reduction rate of proteinuria three months after treatment predicted clinical remission and CR. 54 patients in the remission group were followed up to the endpoint and 14 of them relapsed with nephroticsyndrome. The presence of a PR versus CR significantly predicted relapse (HR: 40.198, 95%CI: 5.023-333.355, P=0.001). Infection was the most common adverse event. Two patients developed malignancies after onset of cyclophosphamide treatment. Conclusions A high rate of good response and a relatively low rate of adverse events were observed in this study. Baseline proteinuria and reduction rate of proteinuria 3 months after onset of cyclophosphamide regimen were independent predictive factors of response. Compared with CR, PR was predictive of a high probability of relapse.