Long-term outcome and prognostic factors of idiopathic membranous nephropathy in the Chinese population

Background: Idiopathic membranous nephropathy (IMN) is a representative form of nephrotic syndrome in China. Although IMN is thought to run a more benign course in Asian patients than in the Caucasian population, there has been no persuasive study to determine the long-term prognosis and risk factors for IMN in the Chinese population. Methods: A retrospective chart review. All patients admitted to Nanjing Institution of Nephrology from January 1985 to December 2007 with biopsy-proven IMN were enrolled. The primary outcome was the renal survival rate and risk factors at renal biopsy. Result: A total of 217 patients were included in the study, and the overall renal survival rates were 96.9%, 93.5%, and 86.6% at 5, 10, and 15 years after renal biopsy, respectively. When the clinical features at biopsy were evaluated, patients with hypertension (p = 0.023), decreased eGFR (p <0.001), nephrotic-range proteinuria (p = 0.047), elevated urinary NAG (p = 0.045) and RBP (p = 0.007) had a worse prognosis. Cox multivariate analysis showed that decreased eGFR and chronic tubulointerstitial lesion were independent risk factors for ESRF (end-stage renal failure). Conclusion: IMN is a disease with a comparatively good prognosis in the Chinese population, with a renal survival rate of more than 90% at 10 years after renal biopsy. Decreased eGFR at biopsy and chronic tubulointerstitial lesion are independent risk factors of ESRF. Partial or complete remission of proteinuria improved the prognosis.