title: Analysis of glomerular filtration rate, serum cystatin C levels, and renal resistive index values in cirrhosis patients.
abstract: BACKGROUND
  The aim of this study was to evaluate the relation of glomerular filtration rate (GFR) to serum cystatin C levels, renal resistive index (RRI), serum creatinine and creatinine clearance in patients with different stages of cirrhosis.
  
  
  METHODS
  The study sample was 25 cirrhotic patients (10 females and 15 males; mean age 57.3+/-2.04 years), 10 in the compensated stage without ascites and 15 in the decompensated stage with new-onset ascites. None had azotemia nor were on diuretic treatment. The control group comprised 25 healthy adults (11 female and 14 men; mean age 56.56+/-1.91 years). Serum cystatin C, RRI, serum creatinine and creatinine clearance were measured. GFR was determined by technetium(99m)-diethylene triamine pentaacetic acid renal scintigraphy.
  
  
  RESULTS
  Cirrhosis cases had lower mean scintigraphic GFR than controls (64.5+/-4.03 vs. 87.96+/-4.16 mL/min, p<0.05). Serum cystatin C and RRI were significantly higher in the cirrhotic group compared to controls (1.16+/-0.09 mg/L and 0.68+/-0.01 vs. 0.86+/-0.03 mg/L and 0.64+/-0.01, respectively; p<0.05). Subgroup comparative analysis showed that only two parameters, scintigraphic GFR and serum cystatin C, were significantly different between compensated and decompensated cirrhotics (75.62+/-4.9 mL/min and 0.89+/-0.07 mg/L vs. 57.23+/-5.14 mL/min and 1.34+/-0.13 mg/L, respectively; p<0.05). Scintigraphic GFR showed significant correlation with cystatin C, but not with serum creatinine or creatinine clearance (r=-0.877, p<0.05) in decompensated patients. No correlation was observed between scintigraphic GFR and RRI or between serum cystatin C and RRI in all subjects. A receiver operator characteristics curve showed that cystatin C at a cutoff value of 1.01 mg/L can significantly differentiate patients with GFR <70 mL/min with 80% sensitivity and 80% specificity.
  
  
  CONCLUSIONS
  Serum cystatin C, but not serum creatinine or RRI measurement, correlates with GFR in each stage of liver failure and has a significant diagnostic advantage in detecting lower GFR in such cases.
authors.affiliation: Department of Internal Medicine, Clinic of Gastroenterology, School of Medicine, Zonguldak Karaelmas University, Zonguldak, Turkey. yucel_u@yahoo.com
authors.forename: Yucel
authors.initials: Y
authors.lastname: Ustundag
authors.forename: Ufuk
authors.initials: U
authors.lastname: Samsar
authors.forename: Sereften
authors.initials: S
authors.lastname: Acikgoz
authors.forename: Mehmet
authors.initials: M
authors.lastname: Cabuk
authors.forename: Sibel
authors.initials: S
authors.lastname: Kiran
authors.forename: Eyup
authors.initials: E
authors.lastname: Kulah
authors.forename: Selim
authors.initials: S
authors.lastname: Aydemir
mesh_terms: D003404:Creatinine / Q000097:blood*; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000150:complications / Q000503:physiopathology; D007677:Kidney Function Tests; D008103:Liver Cirrhosis / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D017556:Technetium Compounds
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D017556:Technetium Compounds; D003404:Creatinine