title: Defining the at risk patients for contrast induced nephropathy after coronary angiography; 24-h urine creatinine versus Cockcroft-Gault equation or serum creatinine level.
abstract: BACKGROUND
  Definitions of chronic kidney disease (CKD) in many catheterization laboratories have relied on the serum creatinine (Scr) rather than glomerular filtration rate (GFR). Regarding that CKD is the primary predisposing factor for contrast induced nephropathy (CIN), we compared the sensitivity of calculated GFR by 24-h Urine creatinine with Cockcroft-Gault (CG) equation and Scr level to define at risk patients for CIN who were undergone coronary angiography (CAG).
  
  
  METHODS
  Two hundred fifty four subjects who were candidate for CAG and had normal creatinine level were enrolled. Before CAG, GFR was calculated from a 24-h urine collection, CG equation and a single Scr sample regarding to previously described protocol. Contrast volume used for each case <100 ml. CIN was defined as a 0.5 mg/dL or 25% elevation in the Scr.
  
  
  RESULTS
  CIN occurred in 10.6%. Baseline GFR, the volume of contrast agent, and diabetes were the independent risk factors for CIN. GFR was less than 60 ml/min/1.73 m2 in 28% and 23.2% of patients regarding to 24-h urine creatinine and CG equation, respectively. In CIN prediction, 24-h urine creatinine estimated GFR had 85.2%, 59.3% and CG equation GFR had 78.9%, 81.1% sensitivity and specificity, respectively.
  
  
  CONCLUSIONS
  Although, GFR estimated by CG equation has less sensitivity than GFR calculated from 24-h creatinine in CIN probability, but it is better than Scr alone and because of cost-effectiveness and convenience using of this method, we suggest at least using CG equation for GFR calculation before CIN, especially in diabetic and/or older than 60 years cases.
authors.affiliation: Department of Cardiology, Ahvaz Jundishapur University of Medical science, Golestan Hospital, Ahvaz, Iran.
authors.forename: Ahmadreza
authors.initials: A
authors.lastname: Assareh
authors.forename: Saeed
authors.initials: S
authors.lastname: Yazdankhah
authors.forename: Ahmad
authors.initials: A
authors.lastname: Ahmadzadeh
authors.forename: Mahdi
authors.initials: M
authors.lastname: Yadollahzadeh
authors.forename: Nasim
authors.initials: N
authors.lastname: Nasehi
authors.forename: Habib
authors.initials: H
authors.lastname: Haybar
keywords: 24-hour urine creatinine; cockcroft-gault equation; contrast induced nephropathy; coronary angiography; glomerular filtration rate; serum creatinine