title: Low glomerular density is a risk factor for progression in idiopathic membranous nephropathy.
abstract: BACKGROUND
  The adverse histological features predicting a progressive loss of renal function in idiopathic membranous nephropathy (IMN), before the establishment of impaired renal function with advanced glomerulosclerosis and/or interstitial fibrosis, are still poorly understood. The present study examined the relationship between the glomerular density (GD; non-sclerotic glomerular number/renal cortical area of biopsy) and the renal prognosis in IMN patients, especially in those without any apparent renal dysfunction at the time of diagnosis.
  
  
  METHODS
  The predictive value of the factors at biopsy, including the GD, on the renal outcome was retrospectively analyzed in the 65 IMN patients with an estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m(2) (mean, 80 mL/min/1.73 m(2)) at biopsy.
  
  
  RESULTS
  The individual values for GD ranged from 1.6 to 6.5/mm(2) with 4-fold variation. A lower GD was associated with progression based on a ≥ 50% reduction in eGFR or reaching to end-stage renal disease. An association between a lower GD and progression was observed, especially in patients with persistent proteinuria of ≥ 1 g/day at follow-up. In contrast, any patients who achieved proteinuria of <1 g/day at follow-up did not show progression regardless of their GD levels. In addition, among the various clinicopathological factors observed, the GD was the only factor at biopsy that independently predicted the slope of the renal function during the observation periods.
  
  
  CONCLUSIONS
  These results suggest that low GD is a plausible risk factor for progression in IMN patients, especially in those that do not achieve a remission of proteinuria during the follow-up.
authors.affiliation: Division of Kidney and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan. nobuotsuboi@aol.com
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tsuboi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawamura
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Utsunomiya
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Hosoya
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D015433:Glomerulonephritis, Membranous / Q000150:complications*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000209:etiology*; D007677:Kidney Function Tests; D007678:Kidney Glomerulus / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011507:Proteinuria / Q000209:etiology / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult