title: Independent or synergistic relationship of proteinuria and glomerular filtration rate on patient and renal survival in patients with glomerulonephritis?
abstract: BACKGROUND
  Glomerular filtration rate (GFR) in patients with chronic kidney disease (CKD) identifies patients at risk for death or end-stage renal disease (ESRD). CKD staging by GFR should incorporate proteinuria to augment risk stratification. We therefore tested the predictive power of the combination of GFR with proteinuria in patients with different histologically-diagnosed types of glomerulonephritis (GN).
  
  
  METHODS
  In a retrospective analysis, 2,687 patients with different forms of GN from 123 Austrian centres were investigated. Full data sets were available from 1,892 subjects. Classes of CKD on the basis of estimated GFR (eGFR) and of proteinuria grouped as <1, 1-3.5, and >3.5 g/24 h were tested for their association with all-cause mortality and ESRD.
  
  
  RESULTS
  During a median follow-up of 130 months [interquartile range (IQR) 90; 178] 478 patients (25.3 %) died. Median eGFR was 49 ml/min/1.73 m(2) (IQR 24; 81) and proteinuria 3.8 g/24 h (IQR 1.7; 8.0). Adjusted multivariate Cox regression indicated that renal survival but not overall survival is related to proteinuria >3.5 g/24 h [as opposed to <1 g/24 h; hazard ratio (HR) 1.91] and shows progression to ESRD. However, subgroup analyses revealed that this risk with proteinuria >3.5 g/24 h exists only in patients with immunoglobulin (Ig)A GN (HR 4.93), miscellaneous GN (HR 1.74), and CKD stage 5 (HR 2.50). Additionally, proteinuria is a risk factor for renal survival in males more than in females with GN and proteinuria >3.5 g/24 h (HR 1.91).
  
  
  CONCLUSIONS
  Proteinuria is a strong risk factor for renal survival particularly in patients with proteinuria >3.5 g/24 but not for all types of GN, nor for all CKD stages. Proteinuria is not a risk factor for overall survival in patients with GN.
authors.affiliation: Division of Nephrology and Dialysis, Department of Internal Medicine III, General Hospital/Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria. dominikhaider2003@yahoo.de.
authors.forename: Dominik G
authors.initials: DG
authors.lastname: Haider
authors.affiliation: Division of Nephrology and Dialysis, Department of Internal Medicine III, General Hospital/Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Salome
authors.initials: S
authors.lastname: Masghati
authors.affiliation: Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Goliasch
authors.affiliation: Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Valentin
authors.initials: V
authors.lastname: Fuhrmann
authors.affiliation: Department of Clinical Pathology, Medical University of Vienna, Vienna, Austria.
authors.forename: Afschin
authors.initials: A
authors.lastname: Soleiman
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
authors.affiliation: Division of Nephrology and Dialysis, Department of Internal Medicine III, General Hospital/Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Baierl
authors.affiliation: Division of Nephrology and Dialysis, Department of Internal Medicine III, General Hospital/Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Wilfred
authors.initials: W
authors.lastname: Druml
authors.affiliation: Division of Nephrology and Dialysis, Department of Internal Medicine III, General Hospital/Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Walter H
authors.initials: WH
authors.lastname: Hörl
mesh_terms: D000328:Adult; D001317:Austria / Q000453:epidemiology; D016009:Chi-Square Distribution; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D005921:Glomerulonephritis / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D011507:Proteinuria / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors
keywords: Glomerulonephritis; Proteinuria; Survival