title: Assessment of cystatin C and cystatin C-based GFR formulas in reflux nephropathy.
abstract: OBJECTIVE
  Early identification of reflux nephropathy (RN) could reduce the frequency of chronic kidney disease (CKD) caused by vesicoureteral reflux (VUR). We aimed to assess whether cystatin C has value for determining RN in children with VUR.
  
  
  METHODS
  Ninety-three children with VUR were classified into two groups according to the presence of renal parenchymal scarring (RS). Patients with RS were divided into three subgroups according to scar grade. Serum cystatin C, serum creatinine (Scr) and urine creatinine were measured. eGFR values of the patients were calculated with Scr-based, cystatin C-based and combined formulas.
  
  
  RESULTS
  Cystatin C was significantly higher in patients with RS than patients without RS and declined in parallel with grade of RS (p = 0.01). Scr was not significant in patients with and without RS. It was only significant between mild and severe scar subgroups (p < 0.05). All eGFR values were lower in RS (+) patients compared with RS (-) patients. All eGFR equations were negatively correlated with grade of RS (p < 0.05).
  
  
  CONCLUSIONS
  Cystatin C could be a useful marker for identifying the risk and severity of RN in patients with VUR. Renal functions could be more accurately determined with Scr-cystatin C combined eGFR equations.
authors.affiliation: Division of Pediatric Nephrology, Cukurova University School of Medicine, 01330 Adana, Turkey. Electronic address: drsyavuz@gmail.com.
authors.forename: Sevgi
authors.initials: S
authors.lastname: Yavuz
authors.affiliation: Division of Pediatric Nephrology, Cukurova University School of Medicine, 01330 Adana, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Anarat
authors.affiliation: Division of Pediatric Nephrology, Cukurova University School of Medicine, 01330 Adana, Turkey.
authors.forename: Aysun K
authors.initials: AK
authors.lastname: Bayazıt
mesh_terms: D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D002921:Cicatrix / Q000473:pathology; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000209:etiology / Q000473:pathology*; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D014718:Vesico-Ureteral Reflux / Q000097:blood* / Q000150:complications / Q000503:physiopathology
chemical_list: D015415:Biomarkers; D055316:Cystatin C
keywords: Cystatin C; Glomerular filtration rate; Reflux nephropathy; Vesicoureteral reflux