Increasing frequency of idiopathic membranous nephropathy in primary glomerular disease: A 10‐year renal biopsy study from a single C hinese nephrology centre

AIM: To investigate the changing of idiopathic membranous nephropathy (iMN) in China. METHODS: This study retrospectively analyzed renal disease spectrum of 6049 patients who underwent renal biopsy at Peking University First Hospital from January 2003 to December 2012. The patients were grouped into two periods at a 5-year interval: 2003-2007 (period 1) and 2008-2012 (period 2). RESULTS: Among 6049 renal biopsied patients, 3831 (63.3%) patients were diagnosed as primary glomerular disease (PGD). The proportion of nephrotic syndrome (NS) in PGD was significantly higher in period 2 than that in period 1 (1016/2214 [55.0%] vs 682/1617 [42.2%], P = 0.022). The proportion of iMN in PGD increased from 16.8% (217/1617) in period 1 to 29.35% (646/2214) in period 2 in all groups of age (P < 0.001). There was no significant difference of clinical characteristics including age, gender, hypertension, serum cholesterol and proteinuria between the two periods (P > 0.05). However, in young patients with iMN (14-44 years old), the percentage of renal histopathology stage I and stage II of iMN in PGDs was significantly higher in period 2 than that in period 1 (101/1240 [8.15%] vs 210/1340 [15.7%], P < 0.001). CONCLUSION: Our study suggests that the frequency of iMN in PGD in our referral diagnostic centre has doubled over the past 10 years. The increase of adult iMN is mainly due to the increase of early stages of iMN in young patients.