title: Association between urinary type IV collagen level and deterioration of renal function in type 2 diabetic patients without overt proteinuria.
abstract: OBJECTIVE
  Cross-sectional studies have reported increased levels of urinary type IV collagen in diabetic patients with progression of diabetic nephropathy. The aim of this study was to determine the role of urinary type IV collagen in predicting development and progression of early diabetic nephropathy and deterioration of renal function in a longitudinal study.
  
  
  METHODS
  Japanese patients with type 2 diabetes (n = 254, 185 with normoalbuminuria and 69 with microalbuminuria) were enrolled in an observational follow-up study. The associations of urinary type IV collagen with progression of nephropathy and annual decline in estimated glomerular filtration rate (eGFR) were evaluated.
  
  
  RESULTS
  At baseline, urinary type IV collagen levels were higher in patients with microalbuminuria than in those with normoalbuminuria and correlated with urinary beta(2)-microglobulin (beta = 0.57, P < 0.001), diastolic blood pressure (beta = 0.15, P < 0.01), eGFR (beta = 0.15, P < 0.01), and urinary albumin excretion rate (beta = 0.13, P = 0.01) as determined by multivariate regression analysis. In the follow-up study (median duration 8 years), urinary type IV collagen level at baseline was not associated with progression to a higher stage of diabetic nephropathy. However, the level of urinary type IV collagen inversely correlated with the annual decline in eGFR (gamma = -0.34, P < 0.001). Multivariate regression analysis identified urinary type IV collagen, eGFR at baseline, and hypertension as factors associated with the annual decline in eGFR.
  
  
  CONCLUSIONS
  Our results indicate that high urinary excretion of type IV collagen is associated with deterioration of renal function in type 2 diabetic patients without overt proteinuria.
authors.affiliation: Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan. araki@belle.shiga-med.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Araki
authors.forename: Masakazu
authors.initials: M
authors.lastname: Haneda
authors.forename: Daisuke
authors.initials: D
authors.lastname: Koya
authors.forename: Keiji
authors.initials: K
authors.lastname: Isshiki
authors.forename: Shinji
authors.initials: S
authors.lastname: Kume
authors.forename: Toshiro
authors.initials: T
authors.lastname: Sugimoto
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kawai
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nishio
authors.forename: Atsunori
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Takashi
authors.initials: T
authors.lastname: Uzu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maegawa
mesh_terms: D000368:Aged; D024141:Collagen Type IV / Q000652:urine*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology* / Q000652:urine*; D003928:Diabetic Nephropathies / Q000473:pathology / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000503:physiopathology*
chemical_list: D024141:Collagen Type IV