title: Prediction of contrast-induced nephropathy in diabetic patients undergoing elective cardiac catheterization or PCI: role of volume-to-creatinine clearance ratio and iodine dose-to-creatinine clearance ratio.
abstract: OBJECTIVE
  To assess a role of volume-to-creatinine clearance ratio (V/CrCl) and iodine dose-to-creatinine clearance ratio (I-dose/CrCl) in predicting contrast- induced nephropathy (CIN) in diabetic patients undergoing elective cardiac catheterization or percutaneous coronary intervention (PCI).
  
  
  BACKGROUND
  In diabetic patients undergoing cardiac catheterization or PCI, the incidence of CIN is higher than in non-diabetic patients. High doses of contrast media also increase the likelihood of renal dysfunction. The ratio of the volume of contrast media to creatinine clearance (V/CrCl) and iodine dose-to-creatinine clearance (I-dose/CrCl) has been shown to correlate with the area under the curve of contrast media concentration over time and was used to predict the occurrence of CIN in unselected patients. No study has been conducted specifically in diabetic patients undergoing cardiac catheterization or PCI before.
  
  
  METHODS
  We conducted a prospective, single center study. The V/CrCl and I-dose/CrCl were calculated in diabetic patients undergoing elective cardiac catheterization or PCI. An increase in serum creatinine of > 0.5 mg/dl or > 25% by 7 days from baseline was considered CIN. The incidence of CIN was determined. The predictive value of V/CrCl and I-dose/CrCl for CIN were assessed using multivariable logistic regression.
  
  
  RESULTS
  The total number of patients that had been enrolled in the study was 248; Male 50.8%. The overall incidence of CIN was 5.2%. The mean age for the entire population was 65 +/- 9 years; the mean body mass index was 25.6 +/- 4.0 kg/m2; and the mean creatinine clearance was 60.6 +/- 27.4 ml/min. The mean values of V/CrCl for patients with and without CIN were 3.7 +/- 2.9 and 2.2 +/- 1.7 (p = 0.041). The mean values of I-dose/CrCl for patients with and without CIN were 1.31 +/- 0.94 and 0.82 +/- 0.63 (p = 0.042). The receiver-operator characteristic curve analysis indicated that a V/CrCl ratio of 2.60 and I-dose/CrCl of 0.98 were fair predictors of CIN. After adjusting for other known predictors of CIN, a V/CrCl ratio > or = 2.60 remained the only significant predictor of CIN (Odds ratio 5.8; 95% confidence interval 1.7-19.4, p = 0.005).
  
  
  CONCLUSIONS
  A V/CrCl ratio > or = 2.60 was a significant predictor of CIN in diabetic patients undergoing elective cardiac catheterization or PCI.
authors.affiliation: Division of Cardiology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Surapong
authors.initials: S
authors.lastname: Worasuwannarak
authors.forename: Suwatchai
authors.initials: S
authors.lastname: Pornratanarangsi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage*; D019540:Area Under Curve; D006328:Cardiac Catheterization / Q000379:methods*; D003287:Contrast Media / Q000009:adverse effects*; D017023:Coronary Angiography; D003404:Creatinine / Q000097:blood*; D003925:Diabetic Angiopathies / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D015994:Incidence; D007455:Iodine / Q000008:administration & dosage*; D007674:Kidney Diseases / Q000139:chemically induced / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000891:Anti-Infective Agents, Local; D003287:Contrast Media; D007455:Iodine; D003404:Creatinine